fix overdue test case

correctly return pointer to Task inside TaskList.

README.md

@@ -35,10 +35,30 @@ go-todotxt requires Go1.1 or higher.
 			log.Fatal(err)
 		}
 
+		// tasklist now contains a slice of Tasks
 		fmt.Printf("Task 2, todo: %v\n", tasklist[1].Todo)
 		fmt.Printf("Task 3: %v\n", tasklist[2])
 		fmt.Printf("Task 4, has priority: %v\n\n", tasklist[3].HasPriority())
 		fmt.Print(tasklist)
+
+		// Filter list to get only completed tasks
+		completedList := tasklist.Filter(func(t Task) bool {
+			return t.Completed 
+		})
+		fmt.Print(completedList)
+
+		// Add a new empty Task to tasklist
+		task := NewTask()
+		tasklist.AddTask(&task)
+
+		// Or a parsed Task from a string
+		parsedTask, _ := ParseTask("x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12")
+		tasklist.AddTask(parsed)
+
+		// Update an existing task
+		task, _ := tasklist.GetTask(2) // Task pointer
+		task.Todo = "Do something different.."
+		tasklist.WriteToFilename("todo.txt")
 	}
 ```
 

example_test.go

@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package todotxt
+
+import (
+	"fmt"
+	"log"
+)
+
+func ExampleLoadFromFilename() {
+	if tasklist, err := LoadFromFilename("todo.txt"); err != nil {
+		log.Fatal(err)
+	} else {
+		fmt.Print(tasklist) // String representation of TaskList works as expected.
+	}
+
+	// Output:
+	// (A) Call Mom @Phone +Family
+	// (A) Schedule annual checkup +Health
+	// (B) Outline chapter 5 @Computer +Novel
+	// (C) Add cover sheets @Office +TPSReports
+	// Plan backyard herb garden @Home
+	// Pick up milk @GroceryStore
+	// Research self-publishing services @Computer +Novel
+	// x Download Todo.txt mobile app @Phone
+}
+
+func ExampleTaskList_LoadFromFilename() {
+	var tasklist TaskList
+
+	// This will overwrite whatever was in the tasklist before.
+	// Irrelevant here since the list is still empty.
+	if err := tasklist.LoadFromFilename("todo.txt"); err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println(tasklist[0].Todo)      // Text part of first task (Call Mom)
+	fmt.Println(tasklist[2].Contexts)  // Slice of contexts from third task ([Computer])
+	fmt.Println(tasklist[3].Priority)  // Priority of fourth task (C)
+	fmt.Println(tasklist[7].Completed) // Completed flag of eigth task (true)
+	// Output:
+	// Call Mom
+	// [Computer]
+	// C
+	// true
+}

sort.go

@@ -35,7 +35,7 @@ func (tasklist *TaskList) Sort(sortFlag int) error {
 	case SORT_DUE_DATE_ASC, SORT_DUE_DATE_DESC:
 		tasklist.sortByDueDate(sortFlag)
 	default:
-		return errors.New("Unrecognized sort option")
+		return errors.New("unrecognized sort option")
 	}
 	return nil
 }
@@ -68,19 +68,17 @@ func (tasklist *TaskList) sortBy(by func(t1, t2 *Task) bool) *TaskList {
 
 func (tasklist *TaskList) sortByPriority(order int) *TaskList {
 	tasklist.sortBy(func(t1, t2 *Task) bool {
-		if order == SORT_PRIORITY_DESC { // DESC
+		if order == SORT_PRIORITY_ASC { // ASC
-			if t1.HasPriority() && t2.HasPriority() {
-				return t1.Priority > t2.Priority
-			} else {
-				return !t1.HasPriority()
-			}
-		} else { // ASC
 			if t1.HasPriority() && t2.HasPriority() {
 				return t1.Priority < t2.Priority
-			} else {
+			}
 			return t1.HasPriority()
 		}
+		// DESC
+		if t1.HasPriority() && t2.HasPriority() {
+			return t1.Priority > t2.Priority
 		}
+		return !t1.HasPriority()
 	})
 	return tasklist
 }
@@ -89,17 +87,15 @@ func sortByDate(asc bool, hasDate1, hasDate2 bool, date1, date2 time.Time) bool
 	if asc { // ASC
 		if hasDate1 && hasDate2 {
 			return date1.Before(date2)
-		} else {
+		}
 		return hasDate2
 	}
-	} else { // DESC
+	// DESC
 	if hasDate1 && hasDate2 {
 		return date1.After(date2)
-		} else {
+	}
 	return !hasDate2
 }
-	}
-}
 
 func (tasklist *TaskList) sortByCreatedDate(order int) *TaskList {
 	tasklist.sortBy(func(t1, t2 *Task) bool {

sort_test.go

@@ -1,3 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 package todotxt
 
 import (
@@ -14,7 +18,9 @@ func TestTaskSortByPriority(t *testing.T) {
 
 	testTasklist = testTasklist[taskId : taskId+6]
 
-	testTasklist.Sort(SORT_PRIORITY_ASC)
+	if err := testTasklist.Sort(SORT_PRIORITY_ASC); err != nil {
+		t.Fatal(err)
+	}
 
 	testExpected = "(A) 2012-01-30 Call Mom @Call @Phone +Family"
 	testGot = testTasklist[0].Task()
@@ -52,7 +58,9 @@ func TestTaskSortByPriority(t *testing.T) {
 		t.Errorf("Expected Task[6] after Sort() to be [%s], but got [%s]", testExpected, testGot)
 	}
 
-	testTasklist.Sort(SORT_PRIORITY_DESC)
+	if err := testTasklist.Sort(SORT_PRIORITY_DESC); err != nil {
+		t.Fatal(err)
+	}
 
 	testExpected = "x 2014-01-03 Create golang library @Go +go-todotxt due:2014-01-05"
 	testGot = testTasklist[0].Task()
@@ -97,7 +105,9 @@ func TestTaskSortByCreatedDate(t *testing.T) {
 
 	testTasklist = testTasklist[taskId : taskId+5]
 
-	testTasklist.Sort(SORT_CREATED_DATE_ASC)
+	if err := testTasklist.Sort(SORT_CREATED_DATE_ASC); err != nil {
+		t.Fatal(err)
+	}
 
 	testExpected = "x 2014-01-03 Create golang library @Go +go-todotxt due:2014-01-05"
 	testGot = testTasklist[0].Task()
@@ -129,7 +139,9 @@ func TestTaskSortByCreatedDate(t *testing.T) {
 		t.Errorf("Expected Task[5] after Sort() to be [%s], but got [%s]", testExpected, testGot)
 	}
 
-	testTasklist.Sort(SORT_CREATED_DATE_DESC)
+	if err := testTasklist.Sort(SORT_CREATED_DATE_DESC); err != nil {
+		t.Fatal(err)
+	}
 
 	testExpected = "x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12"
 	testGot = testTasklist[0].Task()
@@ -168,7 +180,9 @@ func TestTaskSortByCompletedDate(t *testing.T) {
 
 	testTasklist = testTasklist[taskId : taskId+6]
 
-	testTasklist.Sort(SORT_COMPLETED_DATE_ASC)
+	if err := testTasklist.Sort(SORT_COMPLETED_DATE_ASC); err != nil {
+		t.Fatal(err)
+	}
 
 	testExpected = "x Download Todo.txt mobile app @Phone"
 	testGot = testTasklist[0].Task()
@@ -206,7 +220,9 @@ func TestTaskSortByCompletedDate(t *testing.T) {
 		t.Errorf("Expected Task[6] after Sort() to be [%s], but got [%s]", testExpected, testGot)
 	}
 
-	testTasklist.Sort(SORT_COMPLETED_DATE_DESC)
+	if err := testTasklist.Sort(SORT_COMPLETED_DATE_DESC); err != nil {
+		t.Fatal(err)
+	}
 
 	testExpected = "x 2014-01-04 2014-01-01 Create some more golang library test cases @Go +go-todotxt"
 	testGot = testTasklist[0].Task()
@@ -251,7 +267,9 @@ func TestTaskSortByDueDate(t *testing.T) {
 
 	testTasklist = testTasklist[taskId : taskId+4]
 
-	testTasklist.Sort(SORT_DUE_DATE_ASC)
+	if err := testTasklist.Sort(SORT_DUE_DATE_ASC); err != nil {
+		t.Fatal(err)
+	}
 
 	testExpected = "x 2014-01-02 (B) 2013-12-30 Create golang library test cases @Go +go-todotxt"
 	testGot = testTasklist[0].Task()
@@ -277,7 +295,9 @@ func TestTaskSortByDueDate(t *testing.T) {
 		t.Errorf("Expected Task[4] after Sort() to be [%s], but got [%s]", testExpected, testGot)
 	}
 
-	testTasklist.Sort(SORT_DUE_DATE_DESC)
+	if err := testTasklist.Sort(SORT_DUE_DATE_DESC); err != nil {
+		t.Fatal(err)
+	}
 
 	testExpected = "(B) 2013-12-01 Outline chapter 5 @Computer +Novel Level:5 private:false due:2014-02-17"
 	testGot = testTasklist[0].Task()
@@ -303,3 +323,13 @@ func TestTaskSortByDueDate(t *testing.T) {
 		t.Errorf("Expected Task[4] after Sort() to be [%s], but got [%s]", testExpected, testGot)
 	}
 }
+
+func TestTaskSortError(t *testing.T) {
+	testTasklist.LoadFromFilename(testInputSort)
+
+	if err := testTasklist.Sort(123); err == nil {
+		t.Errorf("Expected Sort() to fail because of unrecognized sort option, but it didn't!")
+	} else if err.Error() != "unrecognized sort option" {
+		t.Error(err)
+	}
+}

task.go

@@ -6,12 +6,29 @@ package todotxt
 
 import (
 	"fmt"
+	"regexp"
 	"sort"
+	"strings"
 	"time"
 )
 
+var (
+	// DateLayout is used for formatting time.Time into todo.txt date format and vice-versa.
+	DateLayout = "2006-01-02"
+
+	priorityRx = regexp.MustCompile(`^(x|x \d{4}-\d{2}-\d{2}|)\s*\(([A-Z])\)\s+`) // Match priority: '(A) ...' or 'x (A) ...' or 'x 2012-12-12 (A) ...'
+	// Match created date: '(A) 2012-12-12 ...' or 'x 2012-12-12 (A) 2012-12-12 ...' or 'x (A) 2012-12-12 ...'or 'x 2012-12-12 2012-12-12 ...' or '2012-12-12 ...'
+	createdDateRx   = regexp.MustCompile(`^(\([A-Z]\)|x \d{4}-\d{2}-\d{2} \([A-Z]\)|x \([A-Z]\)|x \d{4}-\d{2}-\d{2}|)\s*(\d{4}-\d{2}-\d{2})\s+`)
+	completedRx     = regexp.MustCompile(`^x\s+`)                       // Match completed: 'x ...'
+	completedDateRx = regexp.MustCompile(`^x\s*(\d{4}-\d{2}-\d{2})\s+`) // Match completed date: 'x 2012-12-12 ...'
+	addonTagRx      = regexp.MustCompile(`(^|\s+)([\w-]+):(\S+)`)       // Match additional tags date: '... due:2012-12-12 ...'
+	contextRx       = regexp.MustCompile(`(^|\s+)@(\S+)`)               // Match contexts: '@Context ...' or '... @Context ...'
+	projectRx       = regexp.MustCompile(`(^|\s+)\+(\S+)`)              // Match projects: '+Project...' or '... +Project ...')
+)
+
 // Task represents a todo.txt task entry.
 type Task struct {
+	Id             int    // Internal task id.
 	Original       string // Original raw task text.
 	Todo           string // Todo part of task text.
 	Priority       string
@@ -53,12 +70,14 @@ func (task Task) String() string {
 	text += task.Todo
 
 	if len(task.Contexts) > 0 {
+		sort.Strings(task.Contexts)
 		for _, context := range task.Contexts {
 			text += fmt.Sprintf(" @%s", context)
 		}
 	}
 
 	if len(task.Projects) > 0 {
+		sort.Strings(task.Projects)
 		for _, project := range task.Projects {
 			text += fmt.Sprintf(" +%s", project)
 		}
@@ -67,7 +86,7 @@ func (task Task) String() string {
 	if len(task.AdditionalTags) > 0 {
 		// Sort map alphabetically by keys
 		keys := make([]string, 0, len(task.AdditionalTags))
-		for key, _ := range task.AdditionalTags {
+		for key := range task.AdditionalTags {
 			keys = append(keys, key)
 		}
 		sort.Strings(keys)
@@ -83,6 +102,108 @@ func (task Task) String() string {
 	return text
 }
 
+// NewTask creates a new empty Task with default values. (CreatedDate is set to Now())
+func NewTask() Task {
+	task := Task{}
+	task.CreatedDate = time.Now()
+	return task
+}
+
+// ParseTask parses the input text string into a Task struct.
+func ParseTask(text string) (*Task, error) {
+	var err error
+
+	task := Task{}
+	task.Original = strings.Trim(text, "\t\n\r ")
+	task.Todo = task.Original
+
+	// Check for completed
+	if completedRx.MatchString(task.Original) {
+		task.Completed = true
+		// Check for completed date
+		if completedDateRx.MatchString(task.Original) {
+			if date, err := time.Parse(DateLayout, completedDateRx.FindStringSubmatch(task.Original)[1]); err == nil {
+				task.CompletedDate = date
+			} else {
+				return nil, err
+			}
+		}
+
+		// Remove from Todo text
+		task.Todo = completedDateRx.ReplaceAllString(task.Todo, "") // Strip CompletedDate first, otherwise it wouldn't match anymore (^x date...)
+		task.Todo = completedRx.ReplaceAllString(task.Todo, "")     // Strip 'x '
+	}
+
+	// Check for priority
+	if priorityRx.MatchString(task.Original) {
+		task.Priority = priorityRx.FindStringSubmatch(task.Original)[2]
+		task.Todo = priorityRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
+	}
+
+	// Check for created date
+	if createdDateRx.MatchString(task.Original) {
+		if date, err := time.Parse(DateLayout, createdDateRx.FindStringSubmatch(task.Original)[2]); err == nil {
+			task.CreatedDate = date
+			task.Todo = createdDateRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
+		} else {
+			return nil, err
+		}
+	}
+
+	// function for collecting projects/contexts as slices from text
+	getSlice := func(rx *regexp.Regexp) []string {
+		matches := rx.FindAllStringSubmatch(task.Original, -1)
+		slice := make([]string, 0, len(matches))
+		seen := make(map[string]bool, len(matches))
+		for _, match := range matches {
+			word := strings.Trim(match[2], "\t\n\r ")
+			if _, found := seen[word]; !found {
+				slice = append(slice, word)
+				seen[word] = true
+			}
+		}
+		sort.Strings(slice)
+		return slice
+	}
+
+	// Check for contexts
+	if contextRx.MatchString(task.Original) {
+		task.Contexts = getSlice(contextRx)
+		task.Todo = contextRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
+	}
+
+	// Check for projects
+	if projectRx.MatchString(task.Original) {
+		task.Projects = getSlice(projectRx)
+		task.Todo = projectRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
+	}
+
+	// Check for additional tags
+	if addonTagRx.MatchString(task.Original) {
+		matches := addonTagRx.FindAllStringSubmatch(task.Original, -1)
+		tags := make(map[string]string, len(matches))
+		for _, match := range matches {
+			key, value := match[2], match[3]
+			if key == "due" { // due date is a known addon tag, it has its own struct field
+				if date, err := time.Parse(DateLayout, value); err == nil {
+					task.DueDate = date
+				} else {
+					return nil, err
+				}
+			} else if key != "" && value != "" {
+				tags[key] = value
+			}
+		}
+		task.AdditionalTags = tags
+		task.Todo = addonTagRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
+	}
+
+	// Trim any remaining whitespaces from Todo text
+	task.Todo = strings.Trim(task.Todo, "\t\n\r\f ")
+
+	return &task, err
+}
+
 // Task returns a complete task string in todo.txt format.
 // See *Task.String() for further information.
 func (task *Task) Task() string {
@@ -106,7 +227,25 @@ func (task *Task) HasDueDate() bool {
 
 // HasCompletedDate returns true if the task has a completed date.
 func (task *Task) HasCompletedDate() bool {
-	return !task.CompletedDate.IsZero()
+	return !task.CompletedDate.IsZero() && task.Completed
+}
+
+// Complete sets Task.Completed to 'true' if the task was not already completed.
+// Also sets Task.CompletedDate to time.Now()
+func (task *Task) Complete() {
+	if !task.Completed {
+		task.Completed = true
+		task.CompletedDate = time.Now()
+	}
+}
+
+// Reopen sets Task.Completed to 'false' if the task was completed.
+// Also resets Task.CompletedDate.
+func (task *Task) Reopen() {
+	if task.Completed {
+		task.Completed = false
+		task.CompletedDate = time.Date(1, 1, 1, 0, 0, 0, 0, time.UTC) // time.IsZero() value
+	}
 }
 
 // IsOverdue returns true if due date is in the past.
@@ -116,9 +255,8 @@ func (task *Task) HasCompletedDate() bool {
 func (task *Task) IsOverdue() bool {
 	if task.HasDueDate() {
 		return task.DueDate.Before(time.Now())
-	} else {
-		return false
 	}
+	return false
 }
 
 // Due returns the duration passed since due date, or until due date from now.
@@ -129,7 +267,6 @@ func (task *Task) IsOverdue() bool {
 func (task *Task) Due() time.Duration {
 	if task.IsOverdue() {
 		return time.Now().Sub(task.DueDate)
-	} else {
+	}
 	return task.DueDate.Sub(time.Now())
 }
-}

task_test.go

@@ -1,3 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 package todotxt
 
 import (
@@ -9,6 +13,184 @@ var (
 	testInputTask = "testdata/task_todo.txt"
 )
 
+func TestNewTask(t *testing.T) {
+	task := NewTask()
+
+	testExpected = 0
+	testGot = task.Id
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to have default Id [%d], but got [%d]", testExpected, testGot)
+	}
+
+	testExpected = ""
+	testGot = task.Original
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to be empty, but got [%s]", testGot)
+	}
+
+	testExpected = ""
+	testGot = task.Todo
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to be empty, but got [%s]", testGot)
+	}
+
+	testExpected = false
+	testGot = task.HasPriority()
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to have no priority, but got [%v]", testGot)
+	}
+
+	testExpected = 0
+	testGot = len(task.Projects)
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to have %d projects, but got [%d]", testExpected, testGot)
+	}
+
+	testExpected = 0
+	testGot = len(task.Contexts)
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to have %d contexts, but got [%d]", testExpected, testGot)
+	}
+
+	testExpected = 0
+	testGot = len(task.AdditionalTags)
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to have %d additional tags, but got [%d]", testExpected, testGot)
+	}
+
+	testExpected = true
+	testGot = task.HasCreatedDate()
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to have a created date, but got [%v]", testGot)
+	}
+
+	testExpected = false
+	testGot = task.HasCompletedDate()
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to not have a completed date, but got [%v]", testGot)
+	}
+
+	testExpected = false
+	testGot = task.HasDueDate()
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to not have a due date, but got [%v]", testGot)
+	}
+
+	testExpected = false
+	testGot = task.Completed
+	if testGot != testExpected {
+		t.Errorf("Expected new Task to not be completed, but got [%v]", testGot)
+	}
+}
+
+func TestParseTask(t *testing.T) {
+	task, err := ParseTask("x (C) 2014-01-01 @Go due:2014-01-12 Create golang library documentation +go-todotxt   ")
+	if err != nil {
+		t.Error(err)
+	}
+
+	testExpected = "x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12"
+	testGot = task.Task()
+	if testGot != testExpected {
+		t.Errorf("Expected Task to be [%s], but got [%s]", testExpected, testGot)
+	}
+
+	testExpected = 0
+	testGot = task.Id
+	if testGot != testExpected {
+		t.Errorf("Expected Task to have default Id [%d], but got [%d]", testExpected, testGot)
+	}
+
+	testExpected = "x (C) 2014-01-01 @Go due:2014-01-12 Create golang library documentation +go-todotxt"
+	testGot = task.Original
+	if testGot != testExpected {
+		t.Errorf("Expected Task to be [%s], but got [%s]", testExpected, testGot)
+	}
+
+	testExpected = "Create golang library documentation"
+	testGot = task.Todo
+	if testGot != testExpected {
+		t.Errorf("Expected Task to be [%s], but got [%s]", testExpected, testGot)
+	}
+
+	testExpected = true
+	testGot = task.HasPriority()
+	if testGot != testExpected {
+		t.Errorf("Expected Task to have no priority, but got [%v]", testGot)
+	}
+
+	testExpected = "C"
+	testGot = task.Priority
+	if testGot != testExpected {
+		t.Errorf("Expected Task to have priority [%v], but got [%v]", testExpected, testGot)
+	}
+
+	testExpected = 1
+	testGot = len(task.Projects)
+	if testGot != testExpected {
+		t.Errorf("Expected Task to have %d projects, but got [%d]", testExpected, testGot)
+	}
+
+	testExpected = 1
+	testGot = len(task.Contexts)
+	if testGot != testExpected {
+		t.Errorf("Expected Task to have %d contexts, but got [%d]", testExpected, testGot)
+	}
+
+	testExpected = 0
+	testGot = len(task.AdditionalTags)
+	if testGot != testExpected {
+		t.Errorf("Expected Task to have %d additional tags, but got [%d]", testExpected, testGot)
+	}
+
+	testExpected = true
+	testGot = task.HasCreatedDate()
+	if testGot != testExpected {
+		t.Errorf("Expected Task to have a created date, but got [%v]", testGot)
+	}
+
+	testExpected = false
+	testGot = task.HasCompletedDate()
+	if testGot != testExpected {
+		t.Errorf("Expected Task to not have a completed date, but got [%v]", testGot)
+	}
+
+	testExpected = true
+	testGot = task.HasDueDate()
+	if testGot != testExpected {
+		t.Errorf("Expected Task to have a due date, but got [%v]", testGot)
+	}
+
+	testExpected = true
+	testGot = task.Completed
+	if testGot != testExpected {
+		t.Errorf("Expected Task to be completed, but got [%v]", testGot)
+	}
+}
+
+func TestTaskId(t *testing.T) {
+	testTasklist.LoadFromFilename(testInputTask)
+
+	taskId := 1
+	testGot = testTasklist[taskId-1].Id
+	if testGot != taskId {
+		t.Errorf("Expected Task[%d] to have Id [%d], but got [%d]", taskId, taskId, testGot)
+	}
+
+	taskId = 5
+	testGot = testTasklist[taskId-1].Id
+	if testGot != taskId {
+		t.Errorf("Expected Task[%d] to have Id [%d], but got [%d]", taskId, taskId, testGot)
+	}
+
+	taskId = 27
+	testGot = testTasklist[taskId-1].Id
+	if testGot != taskId {
+		t.Errorf("Expected Task[%d] to have Id [%d], but got [%d]", taskId, taskId, testGot)
+	}
+	taskId++
+}
+
 func TestTaskString(t *testing.T) {
 	testTasklist.LoadFromFilename(testInputTask)
 	taskId := 1
@@ -263,21 +445,21 @@ func TestTaskCompleted(t *testing.T) {
 	testExpected = true
 	testGot = testTasklist[taskId-1].Completed
 	if testGot != testExpected {
-		t.Errorf("Expected Task[%d] not to be completed, but got '%v'", taskId, testGot)
+		t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
 	}
 	taskId++
 
 	testExpected = true
 	testGot = testTasklist[taskId-1].Completed
 	if testGot != testExpected {
-		t.Errorf("Expected Task[%d] not to be completed, but got '%v'", taskId, testGot)
+		t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
 	}
 	taskId++
 
 	testExpected = true
 	testGot = testTasklist[taskId-1].Completed
 	if testGot != testExpected {
-		t.Errorf("Expected Task[%d] not to be completed, but got '%v'", taskId, testGot)
+		t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
 	}
 	taskId++
 
@@ -379,6 +561,145 @@ func TestTaskIsOverdue(t *testing.T) {
 		t.Errorf("Expected Task[%d] to be due since 72 hours, but got '%v'", taskId, testGot)
 	}
 	taskId++
+
+	testGot = testTasklist[taskId-1].IsOverdue()
+	if testGot.(bool) {
+		t.Errorf("Expected Task[%d] not to be overdue, but got '%v'", taskId, testGot)
+	}
+	taskId++
+}
+
+func TestTaskComplete(t *testing.T) {
+	testTasklist.LoadFromFilename(testInputTask)
+	taskId := 44
+
+	// first 4 tasks should all match the same tests
+	for i := 0; i < 4; i++ {
+		testExpected = false
+		testGot = testTasklist[taskId-1].Completed
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] not to be completed, but got '%v'", taskId, testGot)
+		}
+		testGot = testTasklist[taskId-1].HasCompletedDate()
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] not to have a completed date, but got '%v'", taskId, testGot)
+		}
+		testTasklist[taskId-1].Complete()
+		testExpected = true
+		testGot = testTasklist[taskId-1].Completed
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
+		}
+		testGot = testTasklist[taskId-1].HasCompletedDate()
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to have a completed date, but got '%v'", taskId, testGot)
+		}
+		testExpected = time.Now().Format(DateLayout)
+		testGot = testTasklist[taskId-1].CompletedDate.Format(DateLayout)
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to have a completed date of '%v', but got '%v'", taskId, testExpected, testGot)
+		}
+		taskId++
+	}
+
+	testExpected = true
+	testGot = testTasklist[taskId-1].Completed
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
+	}
+	testGot = testTasklist[taskId-1].HasCompletedDate()
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to have a completed date, but got '%v'", taskId, testGot)
+	}
+	testTasklist[taskId-1].Complete()
+	testGot = testTasklist[taskId-1].Completed // should be unchanged
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
+	}
+	testGot = testTasklist[taskId-1].HasCompletedDate() // should be unchanged
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to have a completed date, but got '%v'", taskId, testGot)
+	}
+	testExpected = "2012-01-01" // should be unchanged
+	testGot = testTasklist[taskId-1].CompletedDate.Format(DateLayout)
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to have a completed date of '%v', but got '%v'", taskId, testExpected, testGot)
+	}
+	taskId++
+}
+
+func TestTaskReopen(t *testing.T) {
+	testTasklist.LoadFromFilename(testInputTask)
+	taskId := 49
+
+	// the first 2 tasks should match the same tests
+	for i := 0; i < 2; i++ {
+		testExpected = true
+		testGot = testTasklist[taskId-1].Completed
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
+		}
+		testExpected = false
+		testGot = testTasklist[taskId-1].HasCompletedDate()
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to have a completed date, but got '%v'", taskId, testGot)
+		}
+		testTasklist[taskId-1].Reopen()
+		testExpected = false
+		testGot = testTasklist[taskId-1].Completed
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to not be completed, but got '%v'", taskId, testGot)
+		}
+		testGot = testTasklist[taskId-1].HasCompletedDate()
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to not have a completed date, but got '%v'", taskId, testGot)
+		}
+		taskId++
+	}
+
+	// the next 3 tasks should all match the same tests
+	for i := 0; i < 3; i++ {
+		testExpected = true
+		testGot = testTasklist[taskId-1].Completed
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
+		}
+		testGot = testTasklist[taskId-1].HasCompletedDate()
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to have a completed date, but got '%v'", taskId, testGot)
+		}
+		testTasklist[taskId-1].Reopen()
+		testExpected = false
+		testGot = testTasklist[taskId-1].Completed
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to not be completed, but got '%v'", taskId, testGot)
+		}
+		testGot = testTasklist[taskId-1].HasCompletedDate()
+		if testGot != testExpected {
+			t.Errorf("Expected Task[%d] to not have a completed date, but got '%v'", taskId, testGot)
+		}
+		taskId++
+	}
+
+	testExpected = false
+	testGot = testTasklist[taskId-1].Completed
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
+	}
+	testGot = testTasklist[taskId-1].HasCompletedDate()
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to have a completed date, but got '%v'", taskId, testGot)
+	}
+	testTasklist[taskId-1].Reopen()
+	testGot = testTasklist[taskId-1].Completed // should be unchanged
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be completed, but got '%v'", taskId, testGot)
+	}
+	testGot = testTasklist[taskId-1].HasCompletedDate() // should be unchanged
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to have a completed date, but got '%v'", taskId, testGot)
+	}
+	taskId++
 }
 
 func compareSlices(list1 []string, list2 []string) bool {

testdata/ouput_todo.txt

@@ -1,6 +1,6 @@
 2013-02-22 Pick up milk @GroceryStore
 x Download Todo.txt mobile app @Phone
-(B) 2013-12-01 Outline chapter 5 @Computer +Novel Level:5 private:false due:2014-02-17
+(C) 2013-12-01 Go home! @Computer +Novel Level:5 private:false due:2011-11-11
 x 2014-01-02 (B) 2013-12-30 Create golang library test cases @Go +go-todotxt
 x 2014-01-03 2014-01-01 Create some more golang library test cases @Go +go-todotxt
 (B) 2013-12-01 Outline chapter 5 @Computer +Novel Level:5 private:false due:2014-02-17

testdata/task_todo.txt

@@ -57,5 +57,22 @@ x 2014-01-03 2014-01-01 Create some more golang library test cases @Go +go-todot
 
 # Overdue test cases
 x 2014-01-04 (B) 2013-12-30 Create golang library @Go +go-todotxt due:2014-01-02
-(B) 2013-12-01 private:false Outline chapter 5 +Novel @Computer due:2017-07-17 Level:5 
+(B) 2013-12-01 private:false Outline chapter 5 +Novel @Computer due:2027-07-17 Level:5
 Research self-publishing services +Novel +Novel +Novel due:2014-01-01
+x 2014-01-03 2014-01-01 Create some more golang library test cases @Go +go-todotxt
+
+# Complete test cases
+Create golang library @Go +go-todotxt due:2014-01-05
+(A) @Phone Call Mom @Call +Family
+2014-01-03 Create golang library @Go +go-todotxt due:2014-01-05
+(B) 2013-12-30 Create golang library test cases @Go +go-todotxt
+x 2012-01-01 More Go!
+
+# Reopen test cases
+x Download Todo.txt mobile app @Phone
+x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12
+x 2014-01-03 Create golang library @Go +go-todotxt due:2014-01-05
+x 2014-01-02 (B) 2013-12-30 Create golang library test cases @Go +go-todotxt
+x 2014-01-03 2014-01-01 Create some more golang library test cases @Go +go-todotxt
+(B) 2013-12-30 Create golang library test cases @Go +go-todotxt
+

testdata/tasklist_completedDate_error.txt

@@ -0,0 +1,6 @@
+x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12
+x Download Todo.txt mobile app @Phone
+x 2014-01-03 Create golang library @Go +go-todotxt due:2014-01-05
+x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12
+x 2014-01-02 (B) 2013-12-30 Create golang library test cases @Go +go-todotxt
+x 2014-25-04 2014-01-01 Create some more golang library test cases @Go +go-todotxt

testdata/tasklist_createdDate_error.txt

@@ -0,0 +1,5 @@
+2013-02-22 Pick up milk @GroceryStore
+x Download Todo.txt mobile app @Phone    
+(B) 2013-13-01 private:false Outline chapter 5 +Novel @Computer Level:5 due:2014-02-17
+x 2014-01-02 (B) 2013-12-30 Create golang library test cases @Go +go-todotxt
+x 2014-01-03 2014-01-01 Create some more golang library test cases @Go +go-todotxt

testdata/tasklist_dueDate_error.txt

@@ -0,0 +1,5 @@
+B) 2013-12-01 private:false Outline chapter 5 +Novel @Computer Level:5 due:2014-02-17
+x 2014-01-02 (B) 2013-12-30 Create golang library test cases @Go +go-todotxt
+x 2014-01-03 2014-01-01 Create some more golang library test cases @Go +go-todotxt
+(B) 2013-12-01 private:false Outline chapter 5 +Novel @Computer Level:5 due:2014-02-32
+x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12

todotxt.go

@@ -10,39 +10,32 @@ package todotxt
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
-	"regexp"
-	"sort"
 	"strings"
-	"time"
 )
 
 // TaskList represents a list of todo.txt task entries.
 // It is usually loaded from a whole todo.txt file.
 type TaskList []Task
 
-// IgnoreComments can be set to 'false', in order to revert to more standard todo.txt behaviour.
+// IgnoreComments can be set to 'false', in order to revert to a more standard todo.txt behaviour.
 // The todo.txt format does not define comments.
 var (
-	// Used for formatting time.Time into todo.txt date format and vice-versa.
+	// IgnoreComments is used to switch ignoring of comments (lines starting with "#").
-	DateLayout = "2006-01-02"
+	// If this is set to 'false', then lines starting with "#" will be parsed as tasks.
-	// Ignores comments (Lines/Text starting with "#").
 	IgnoreComments = true
-
-	// unexported vars
-	priorityRx = regexp.MustCompile(`^(x|x \d{4}-\d{2}-\d{2}|)\s*\(([A-Z])\)\s+`) // Match priority: '(A) ...' or 'x (A) ...' or 'x 2012-12-12 (A) ...'
-	// Match created date: '(A) 2012-12-12 ...' or 'x 2012-12-12 (A) 2012-12-12 ...' or 'x (A) 2012-12-12 ...'or 'x 2012-12-12 2012-12-12 ...' or '2012-12-12 ...'
-	createdDateRx   = regexp.MustCompile(`^(\([A-Z]\)|x \d{4}-\d{2}-\d{2} \([A-Z]\)|x \([A-Z]\)|x \d{4}-\d{2}-\d{2}|)\s*(\d{4}-\d{2}-\d{2})\s+`)
-	completedRx     = regexp.MustCompile(`^x\s+`)                       // Match completed: 'x ...'
-	completedDateRx = regexp.MustCompile(`^x\s*(\d{4}-\d{2}-\d{2})\s+`) // Match completed date: 'x 2012-12-12 ...'
-	addonTagRx      = regexp.MustCompile(`(^|\s+)([\w-]+):(\S+)`)       // Match additional tags date: '... due:2012-12-12 ...'
-	contextRx       = regexp.MustCompile(`(^|\s+)@(\S+)`)               // Match contexts: '@Context ...' or '... @Context ...'
-	projectRx       = regexp.MustCompile(`(^|\s+)\+(\S+)`)              // Match projects: '+Project...' or '... +Project ...'
 )
 
-// String returns a complete tasklist string in todo.txt format.
+// NewTaskList creates a new empty TaskList.
+func NewTaskList() TaskList {
+	tasklist := TaskList{}
+	return tasklist
+}
+
+// String returns a complete list of tasks in todo.txt format.
 func (tasklist TaskList) String() (text string) {
 	for _, task := range tasklist {
 		text += fmt.Sprintf("%s\n", task.String())
@@ -50,6 +43,84 @@ func (tasklist TaskList) String() (text string) {
 	return text
 }
 
+// AddTask appends a Task to the current TaskList and takes care to set the Task.Id correctly, modifying the Task by the given pointer!
+func (tasklist *TaskList) AddTask(task *Task) {
+	task.Id = 0
+	for _, t := range *tasklist {
+		if t.Id > task.Id {
+			task.Id = t.Id
+		}
+	}
+	task.Id += 1
+
+	*tasklist = append(*tasklist, *task)
+}
+
+// GetTask returns a Task by given task 'id' from the TaskList. The returned Task pointer can be used to update the Task inside the TaskList.
+// Returns an error if Task could not be found.
+func (tasklist *TaskList) GetTask(id int) (*Task, error) {
+	for i := range *tasklist {
+		if ([]Task(*tasklist))[i].Id == id {
+			return &([]Task(*tasklist))[i], nil
+		}
+	}
+	return nil, errors.New("task not found")
+}
+
+// RemoveTaskById removes any Task with given Task 'id' from the TaskList.
+// Returns an error if no Task was removed.
+func (tasklist *TaskList) RemoveTaskById(id int) error {
+	var newList TaskList
+
+	found := false
+	for _, t := range *tasklist {
+		if t.Id != id {
+			newList = append(newList, t)
+		} else {
+			found = true
+		}
+	}
+	if !found {
+		return errors.New("task not found")
+	}
+
+	*tasklist = newList
+	return nil
+}
+
+// RemoveTask removes any Task from the TaskList with the same String representation as the given Task.
+// Returns an error if no Task was removed.
+func (tasklist *TaskList) RemoveTask(task Task) error {
+	var newList TaskList
+
+	found := false
+	for _, t := range *tasklist {
+		if t.String() != task.String() {
+			newList = append(newList, t)
+		} else {
+			found = true
+		}
+	}
+	if !found {
+		return errors.New("task not found")
+	}
+
+	*tasklist = newList
+	return nil
+}
+
+// Filter filters the current TaskList for the given predicate (a function that takes a task as input and returns a bool),
+// and returns a new TaskList. The original TaskList is not modified.
+func (tasklist *TaskList) Filter(predicate func(Task) bool) *TaskList {
+	var newList TaskList
+	for _, t := range *tasklist {
+		if predicate(t) {
+			newList = append(newList, t)
+		}
+	}
+	return &newList
+}
+
 // LoadFromFile loads a TaskList from *os.File.
 //
 // Using *os.File instead of a filename allows to also use os.Stdin.
@@ -58,102 +129,24 @@ func (tasklist TaskList) String() (text string) {
 func (tasklist *TaskList) LoadFromFile(file *os.File) error {
 	*tasklist = []Task{} // Empty tasklist
 
+	taskId := 1
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
-		task := Task{}
+		text := strings.Trim(scanner.Text(), "\t\n\r ") // Read line
-		task.Original = strings.Trim(scanner.Text(), "\t\n\r ") // Read line
-		task.Todo = task.Original
 
 		// Ignore blank or comment lines
-		if task.Todo == "" || (IgnoreComments && strings.HasPrefix(task.Todo, "#")) {
+		if text == "" || (IgnoreComments && strings.HasPrefix(text, "#")) {
 			continue
 		}
 
-		// Check for completed
+		task, err := ParseTask(text)
-		if completedRx.MatchString(task.Original) {
+		if err != nil {
-			task.Completed = true
-			// Check for completed date
-			if completedDateRx.MatchString(task.Original) {
-				if date, err := time.Parse(DateLayout, completedDateRx.FindStringSubmatch(task.Original)[1]); err != nil {
 			return err
-				} else {
-					task.CompletedDate = date
-				}
 		}
+		task.Id = taskId
 
-			// Remove from Todo text
+		*tasklist = append(*tasklist, *task)
-			task.Todo = completedDateRx.ReplaceAllString(task.Todo, "") // Strip CompletedDate first, otherwise it wouldn't match anymore (^x date...)
+		taskId++
-			task.Todo = completedRx.ReplaceAllString(task.Todo, "")     // Strip 'x '
-		}
-
-		// Check for priority
-		if priorityRx.MatchString(task.Original) {
-			task.Priority = priorityRx.FindStringSubmatch(task.Original)[2]
-			task.Todo = priorityRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
-		}
-
-		// Check for created date
-		if createdDateRx.MatchString(task.Original) {
-			if date, err := time.Parse(DateLayout, createdDateRx.FindStringSubmatch(task.Original)[2]); err != nil {
-				return err
-			} else {
-				task.CreatedDate = date
-				task.Todo = createdDateRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
-			}
-		}
-
-		// function for collecting projects/contexts as slices from text
-		getSlice := func(rx *regexp.Regexp) []string {
-			matches := rx.FindAllStringSubmatch(task.Original, -1)
-			slice := make([]string, 0, len(matches))
-			seen := make(map[string]bool, len(matches))
-			for _, match := range matches {
-				word := strings.Trim(match[2], "\t\n\r ")
-				if _, found := seen[word]; !found {
-					slice = append(slice, word)
-					seen[word] = true
-				}
-			}
-			sort.Strings(slice)
-			return slice
-		}
-
-		// Check for contexts
-		if contextRx.MatchString(task.Original) {
-			task.Contexts = getSlice(contextRx)
-			task.Todo = contextRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
-		}
-
-		// Check for projects
-		if projectRx.MatchString(task.Original) {
-			task.Projects = getSlice(projectRx)
-			task.Todo = projectRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
-		}
-
-		// Check for additional tags
-		if addonTagRx.MatchString(task.Original) {
-			matches := addonTagRx.FindAllStringSubmatch(task.Original, -1)
-			tags := make(map[string]string, len(matches))
-			for _, match := range matches {
-				key, value := match[2], match[3]
-				if key == "due" { // due date is a known addon tag, it has its own struct field
-					if date, err := time.Parse(DateLayout, value); err != nil {
-						return err
-					} else {
-						task.DueDate = date
-					}
-				} else if key != "" && value != "" {
-					tags[key] = value
-				}
-			}
-			task.AdditionalTags = tags
-			task.Todo = addonTagRx.ReplaceAllString(task.Todo, "") // Remove from Todo text
-		}
-
-		// Trim any remaining whitespaces from Todo text
-		task.Todo = strings.Trim(task.Todo, "\t\n\r\f ")
-
-		*tasklist = append(*tasklist, task)
 	}
 	if err := scanner.Err(); err != nil {
 		return err
@@ -187,7 +180,7 @@ func (tasklist *TaskList) LoadFromFilename(filename string) error {
 
 // WriteToFilename writes a TaskList to the specified file (most likely called "todo.txt").
 func (tasklist *TaskList) WriteToFilename(filename string) error {
-	return ioutil.WriteFile(filename, []byte(tasklist.String()), 0644)
+	return ioutil.WriteFile(filename, []byte(tasklist.String()), 0640)
 }
 
 // LoadFromFile loads and returns a TaskList from *os.File.
@@ -195,8 +188,10 @@ func (tasklist *TaskList) WriteToFilename(filename string) error {
 // Using *os.File instead of a filename allows to also use os.Stdin.
 func LoadFromFile(file *os.File) (TaskList, error) {
 	tasklist := TaskList{}
-	err := tasklist.LoadFromFile(file)
+	if err := tasklist.LoadFromFile(file); err != nil {
-	return tasklist, err
+		return nil, err
+	}
+	return tasklist, nil
 }
 
 // WriteToFile writes a TaskList to *os.File.
@@ -209,8 +204,10 @@ func WriteToFile(tasklist *TaskList, file *os.File) error {
 // LoadFromFilename loads and returns a TaskList from a file (most likely called "todo.txt").
 func LoadFromFilename(filename string) (TaskList, error) {
 	tasklist := TaskList{}
-	err := tasklist.LoadFromFilename(filename)
+	if err := tasklist.LoadFromFilename(filename); err != nil {
-	return tasklist, err
+		return nil, err
+	}
+	return tasklist, nil
 }
 
 // WriteToFilename writes a TaskList to the specified file (most likely called "todo.txt").

todotxt_test.go

@@ -8,10 +8,15 @@ import (
 	"io/ioutil"
 	"os"
 	"testing"
+	"time"
 )
 
 var (
 	testInputTasklist                   = "testdata/tasklist_todo.txt"
+	testInputTasklistCreatedDateError   = "testdata/tasklist_createdDate_error.txt"
+	testInputTasklistDueDateError       = "testdata/tasklist_dueDate_error.txt"
+	testInputTasklistCompletedDateError = "testdata/tasklist_completedDate_error.txt"
+	testInputTasklistScannerError       = "testdata/tasklist_scanner_error.txt"
 	testOutput                          = "testdata/ouput_todo.txt"
 	testExpectedOutput                  = "testdata/expected_todo.txt"
 	testTasklist                        TaskList
@@ -33,12 +38,16 @@ func TestLoadFromFile(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		testExpected := string(data)
+		testExpected = string(data)
-		testGot := testTasklist.String()
+		testGot = testTasklist.String()
 		if testGot != testExpected {
 			t.Errorf("Expected TaskList to be [%s], but got [%s]", testExpected, testGot)
 		}
 	}
+
+	if testTasklist, err := LoadFromFile(nil); testTasklist != nil || err == nil {
+		t.Errorf("Expected LoadFromFile to fail, but got TaskList back: [%s]", testTasklist)
+	}
 }
 
 func TestLoadFromFilename(t *testing.T) {
@@ -49,12 +58,16 @@ func TestLoadFromFilename(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		testExpected := string(data)
+		testExpected = string(data)
-		testGot := testTasklist.String()
+		testGot = testTasklist.String()
 		if testGot != testExpected {
 			t.Errorf("Expected TaskList to be [%s], but got [%s]", testExpected, testGot)
 		}
 	}
+
+	if testTasklist, err := LoadFromFilename("some_file_that_does_not_exists.txt"); testTasklist != nil || err == nil {
+		t.Errorf("Expected LoadFromFilename to fail, but got TaskList back: [%s]", testTasklist)
+	}
 }
 
 func TestWriteFile(t *testing.T) {
@@ -92,8 +105,8 @@ func TestWriteFile(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	testExpected := string(data)
+	testExpected = string(data)
-	testGot := testTasklist.String()
+	testGot = testTasklist.String()
 	if testGot != testExpected {
 		t.Errorf("Expected TaskList to be [%s], but got [%s]", testExpected, testGot)
 	}
@@ -134,8 +147,8 @@ func TestTaskListWriteFile(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	testExpected := string(data)
+	testExpected = string(data)
-	testGot := testTasklist.String()
+	testGot = testTasklist.String()
 	if testGot != testExpected {
 		t.Errorf("Expected TaskList to be [%s], but got [%s]", testExpected, testGot)
 	}
@@ -159,8 +172,8 @@ func TestWriteFilename(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	testExpected := string(data)
+	testExpected = string(data)
-	testGot := testTasklist.String()
+	testGot = testTasklist.String()
 	if testGot != testExpected {
 		t.Errorf("Expected TaskList to be [%s], but got [%s]", testExpected, testGot)
 	}
@@ -184,19 +197,326 @@ func TestTaskListWriteFilename(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	testExpected := string(data)
+	testExpected = string(data)
-	testGot := testTasklist.String()
+	testGot = testTasklist.String()
 	if testGot != testExpected {
 		t.Errorf("Expected TaskList to be [%s], but got [%s]", testExpected, testGot)
 	}
 }
 
-func TestTaskListCount(t *testing.T) {
+func TestNewTaskList(t *testing.T) {
-	testTasklist.LoadFromFilename(testInputTasklist)
+	testTasklist := NewTaskList()
 
-	testExpected := 63
+	testExpected = 0
-	testGot := len(testTasklist)
+	testGot = len(testTasklist)
 	if testGot != testExpected {
 		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
 	}
 }
+
+func TestTaskListCount(t *testing.T) {
+	if err := testTasklist.LoadFromFilename(testInputTasklist); err != nil {
+		t.Fatal(err)
+	}
+
+	testExpected = 63
+	testGot = len(testTasklist)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+}
+
+func TestTaskListAddTask(t *testing.T) {
+	if err := testTasklist.LoadFromFilename(testInputTasklist); err != nil {
+		t.Fatal(err)
+	}
+
+	// add new empty task
+	task := NewTask()
+	testTasklist.AddTask(&task)
+
+	testExpected = 64
+	testGot = len(testTasklist)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+
+	taskId := 64
+	testExpected = time.Now().Format(DateLayout) + " " // tasks created by NewTask() have their created date set
+	testGot = testTasklist[taskId-1].String()
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%s], but got [%s]", taskId, testExpected, testGot)
+	}
+	testExpected = 64
+	testGot = testTasklist[taskId-1].Id
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%d], but got [%d]", taskId, testExpected, testGot)
+	}
+	taskId++
+
+	// add parsed task
+	parsed, err := ParseTask("x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12")
+	if err != nil {
+		t.Error(err)
+	}
+	testTasklist.AddTask(parsed)
+
+	testExpected = "x (C) 2014-01-01 Create golang library documentation @Go +go-todotxt due:2014-01-12"
+	testGot = testTasklist[taskId-1].String()
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%s], but got [%s]", taskId, testExpected, testGot)
+	}
+	testExpected = 65
+	testGot = testTasklist[taskId-1].Id
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%d], but got [%d]", taskId, testExpected, testGot)
+	}
+	taskId++
+
+	// add selfmade task
+	createdDate := time.Now()
+	testTasklist.AddTask(&Task{
+		CreatedDate: createdDate,
+		Todo:        "Go shopping..",
+		Contexts:    []string{"GroceryStore"},
+	})
+
+	testExpected = createdDate.Format(DateLayout) + " Go shopping.. @GroceryStore"
+	testGot = testTasklist[taskId-1].String()
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%s], but got [%s]", taskId, testExpected, testGot)
+	}
+	testExpected = 66
+	testGot = testTasklist[taskId-1].Id
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%d], but got [%d]", taskId, testExpected, testGot)
+	}
+	taskId++
+
+	// add task with explicit Id, AddTask() should ignore this!
+	testTasklist.AddTask(&Task{
+		Id: 101,
+	})
+
+	testExpected = 67
+	testGot = testTasklist[taskId-1].Id
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%d], but got [%d]", taskId, testExpected, testGot)
+	}
+	taskId++
+}
+
+func TestTaskListGetTask(t *testing.T) {
+	if err := testTasklist.LoadFromFilename(testInputTasklist); err != nil {
+		t.Fatal(err)
+	}
+
+	taskId := 3
+	task, err := testTasklist.GetTask(taskId)
+	if err != nil {
+		t.Error(err)
+	}
+	testExpected = "(B) 2013-12-01 Outline chapter 5 @Computer +Novel Level:5 private:false due:2014-02-17"
+	testGot = task.String()
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%s], but got [%s]", taskId, testExpected, testGot)
+	}
+	testExpected = 3
+	testGot = testTasklist[taskId-1].Id
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%d], but got [%d]", taskId, testExpected, testGot)
+	}
+	taskId++
+}
+
+func TestTaskListUpdateTask(t *testing.T) {
+	if err := testTasklist.LoadFromFilename(testInputTasklist); err != nil {
+		t.Fatal(err)
+	}
+
+	taskId := 3
+	task, err := testTasklist.GetTask(taskId)
+	if err != nil {
+		t.Error(err)
+	}
+	testExpected = "(B) 2013-12-01 Outline chapter 5 @Computer +Novel Level:5 private:false due:2014-02-17"
+	testGot = task.String()
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%s], but got [%s]", taskId, testExpected, testGot)
+	}
+	testExpected = 3
+	testGot = testTasklist[taskId-1].Id
+	if testGot != testExpected {
+		t.Errorf("Expected Task[%d] to be [%d], but got [%d]", taskId, testExpected, testGot)
+	}
+
+	task.Priority = "C"
+	task.Todo = "Go home!"
+	date, err := time.Parse(DateLayout, "2011-11-11")
+	if err != nil {
+		t.Error(err)
+	}
+	task.DueDate = date
+	testGot := task
+
+	os.Remove(testOutput)
+	if err := testTasklist.WriteToFilename(testOutput); err != nil {
+		t.Fatal(err)
+	}
+	if err := testTasklist.LoadFromFilename(testOutput); err != nil {
+		t.Fatal(err)
+	}
+	testExpected, err := testTasklist.GetTask(taskId)
+	if err != nil {
+		t.Error(err)
+	}
+	if testGot.Task() != testExpected.Task() {
+		t.Errorf("Expected Task to be [%v]\n, but got [%v]", testExpected, testGot)
+	}
+}
+
+func TestTaskListRemoveTaskById(t *testing.T) {
+	if err := testTasklist.LoadFromFilename(testInputTasklist); err != nil {
+		t.Fatal(err)
+	}
+
+	taskId := 10
+	if err := testTasklist.RemoveTaskById(taskId); err != nil {
+		t.Error(err)
+	}
+	testExpected = 62
+	testGot = len(testTasklist)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+	task, err := testTasklist.GetTask(taskId)
+	if err == nil || task != nil {
+		t.Errorf("Expected no Task to be found anymore, but got %v", task)
+	}
+
+	taskId = 27
+	if err := testTasklist.RemoveTaskById(taskId); err != nil {
+		t.Error(err)
+	}
+	testExpected = 61
+	testGot = len(testTasklist)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+	task, err = testTasklist.GetTask(taskId)
+	if err == nil || task != nil {
+		t.Errorf("Expected no Task to be found anymore, but got %v", task)
+	}
+
+	taskId = 99
+	if err := testTasklist.RemoveTaskById(taskId); err == nil {
+		t.Errorf("Expected no Task to be found for removal")
+	}
+}
+
+func TestTaskListRemoveTask(t *testing.T) {
+	if err := testTasklist.LoadFromFilename(testInputTasklist); err != nil {
+		t.Fatal(err)
+	}
+
+	taskId := 52 // Is "unique" in tasklist
+	task, err := testTasklist.GetTask(taskId)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if err := testTasklist.RemoveTask(*task); err != nil {
+		t.Error(err)
+	}
+	testExpected = 62
+	testGot = len(testTasklist)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+	task, err = testTasklist.GetTask(taskId)
+	if err == nil || task != nil {
+		t.Errorf("Expected no Task to be found anymore, but got %v", task)
+	}
+
+	taskId = 2 // Exists 3 times in tasklist
+	task, err = testTasklist.GetTask(taskId)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if err := testTasklist.RemoveTask(*task); err != nil {
+		t.Error(err)
+	}
+	testExpected = 59
+	testGot = len(testTasklist)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+	task, err = testTasklist.GetTask(taskId)
+	if err == nil || task != nil {
+		t.Errorf("Expected no Task to be found anymore, but got %v", task)
+	}
+
+	if err := testTasklist.RemoveTask(NewTask()); err == nil {
+		t.Errorf("Expected no Task to be found for removal")
+	}
+}
+
+func TestTaskListFilter(t *testing.T) {
+	if err := testTasklist.LoadFromFilename(testInputTasklist); err != nil {
+		t.Fatal(err)
+	}
+
+	// Filter list to get only completed tasks
+	completedList := testTasklist.Filter(func(t Task) bool { return t.Completed })
+	testExpected = 33
+	testGot = len(*completedList)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+
+	// Filter list to get only tasks with a due date
+	dueDateList := testTasklist.Filter(func(t Task) bool { return t.HasDueDate() })
+	testExpected = 26
+	testGot = len(*dueDateList)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+
+	// Filter list to get only tasks with "B" priority
+	prioBList := testTasklist.Filter(func(t Task) bool {
+		return t.HasPriority() && t.Priority == "B"
+	})
+	testExpected = 17
+	testGot = len(*prioBList)
+	if testGot != testExpected {
+		t.Errorf("Expected TaskList to contain %d tasks, but got %d", testExpected, testGot)
+	}
+}
+
+func TestTaskListReadErrors(t *testing.T) {
+	if testTasklist, err := LoadFromFilename(testInputTasklistCreatedDateError); testTasklist != nil || err == nil {
+		t.Errorf("Expected LoadFromFilename to fail because of invalid created date, but got TaskList back: [%s]", testTasklist)
+	} else if err.Error() != `parsing time "2013-13-01": month out of range` {
+		t.Error(err)
+	}
+
+	if testTasklist, err := LoadFromFilename(testInputTasklistDueDateError); testTasklist != nil || err == nil {
+		t.Errorf("Expected LoadFromFilename to fail because of invalid due date, but got TaskList back: [%s]", testTasklist)
+	} else if err.Error() != `parsing time "2014-02-32": day out of range` {
+		t.Error(err)
+	}
+
+	if testTasklist, err := LoadFromFilename(testInputTasklistCompletedDateError); testTasklist != nil || err == nil {
+		t.Errorf("Expected LoadFromFilename to fail because of invalid completed date, but got TaskList back: [%s]", testTasklist)
+	} else if err.Error() != `parsing time "2014-25-04": month out of range` {
+		t.Error(err)
+	}
+
+	// really silly test
+	if testTasklist, err := LoadFromFilename(testInputTasklistScannerError); testTasklist != nil || err == nil {
+		t.Errorf("Expected LoadFromFilename to fail because of invalid file, but got TaskList back: [%s]", testTasklist)
+	} else if err.Error() != `bufio.Scanner: token too long` {
+		t.Error(err)
+	}
+}