Add tests for events --filter container=

Signed-off-by: Harald Albers <[email protected]>

cli/command/system/client_test.go

@@ -19,6 +19,7 @@ type fakeClient struct {
 	eventsFn           func(context.Context, events.ListOptions) (<-chan events.Message, <-chan error)
 	containerPruneFunc func(ctx context.Context, pruneFilters filters.Args) (container.PruneReport, error)
 	networkPruneFunc   func(ctx context.Context, pruneFilter filters.Args) (network.PruneReport, error)
+	containerListFunc  func(context.Context, container.ListOptions) ([]container.Summary, error)
 }
 
 func (cli *fakeClient) ServerVersion(ctx context.Context) (types.Version, error) {
@@ -46,3 +47,10 @@ func (cli *fakeClient) NetworksPrune(ctx context.Context, pruneFilter filters.Ar
 	}
 	return network.PruneReport{}, nil
 }
+
+func (cli *fakeClient) ContainerList(ctx context.Context, options container.ListOptions) ([]container.Summary, error) {
+	if cli.containerListFunc != nil {
+		return cli.containerListFunc(ctx, options)
+	}
+	return []container.Summary{}, nil
+}

cli/command/system/completion_test.go

@@ -0,0 +1,45 @@
+package system
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/docker/cli/internal/test"
+	"github.com/docker/cli/internal/test/builders"
+	"github.com/docker/docker/api/types/container"
+	"github.com/spf13/cobra"
+	"gotest.tools/v3/assert"
+)
+
+// Successful completion lists all container names, prefixed with "container=".
+// Filtering the completions by the current word is delegated to the completion script.
+func TestCompleteEventFilterContainer(t *testing.T) {
+	cli := test.NewFakeCli(&fakeClient{
+		containerListFunc: func(_ context.Context, _ container.ListOptions) ([]container.Summary, error) {
+			return []container.Summary{
+				*builders.Container("foo"),
+				*builders.Container("bar"),
+			}, nil
+		},
+	})
+
+	completions, directive := completeFilters(cli)(NewEventsCommand(cli), nil, "container=")
+
+	assert.DeepEqual(t, completions, []string{"container=foo", "container=bar"})
+	assert.Equal(t, directive, cobra.ShellCompDirectiveNoFileComp)
+}
+
+// In case of API errors, no completions are returned.
+func TestCompleteEventFilterContainerAPIError(t *testing.T) {
+	cli := test.NewFakeCli(&fakeClient{
+		containerListFunc: func(_ context.Context, _ container.ListOptions) ([]container.Summary, error) {
+			return nil, errors.New("API error")
+		},
+	})
+
+	completions, directive := completeFilters(cli)(NewEventsCommand(cli), nil, "container=")
+
+	assert.DeepEqual(t, completions, []string{})
+	assert.Equal(t, directive, cobra.ShellCompDirectiveNoFileComp)
+}