Add Len for channel

Author: cschleiden

internal/sync/channel.go

@@ -10,6 +10,8 @@ type Channel[T any] interface {
 	ReceiveNonBlocking() (v T, ok bool)
 
 	Close()
+
+	Len() int
 }
 
 type Receiver[T any] struct {
@@ -52,6 +54,10 @@ type channel[T any] struct {
 	size      int
 }
 
+func (c *channel[T]) Len() int {
+	return len(c.c)
+}
+
 func (c *channel[T]) Close() {
 	c.closed = true
 

internal/sync/channel_test.go

@@ -470,3 +470,47 @@ func Test_CancellationHandler_Remove(t *testing.T) {
 
 	require.Equal(t, 1, f)
 }
+
+func Test_Channel_Len(t *testing.T) {
+	tests := []struct {
+		name     string
+		setup    func(ctx Context) Channel[int]
+		expected int
+	}{
+		{
+			name: "EmptyChannel",
+			setup: func(ctx Context) Channel[int] {
+				return NewChannel[int]()
+			},
+			expected: 0,
+		},
+		{
+			name: "NonEmptyBufferedChannel",
+			setup: func(ctx Context) Channel[int] {
+				c := NewBufferedChannel[int](4)
+				c.Send(ctx, 42)
+				c.Send(ctx, 23)
+				return c
+			},
+			expected: 2,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var actual int
+			ctx := Background()
+
+			cr := NewCoroutine(ctx, func(ctx Context) error {
+				c := tt.setup(ctx)
+				actual = c.Len()
+
+				return nil
+			})
+
+			cr.Execute()
+
+			require.Equal(t, tt.expected, actual)
+		})
+	}
+}

workflow/channel.go

@@ -19,6 +19,9 @@ type Channel[T any] interface {
 
 	// Close closes the channel. This will cause all future send operations to panic.
 	Close()
+
+	// Len returns the number of elements currently in the channel.
+	Len() int
 }
 
 // NewChannel creates a new channel.