From 670f81803feb1252caf58d6477f9515f978ea8c9 Mon Sep 17 00:00:00 2001
From: Sebastiaan van Stijn <github@gone.nl>
Date: Fri, 18 Oct 2024 11:20:38 +0200
Subject: [PATCH] cmd/docker: add tests for flag-completions, and refactor

Remove the registerCompletionFuncForGlobalFlags for now, as
the error it returned was ignored, so it didn't add much
benefit, other than abstracting things.

Split the underlying completion-functions to separate
functions, and add some basic tests for them.

Remove the completions helper, as it now didn't add much,
and it saved having the dependency on the package.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
---
 cmd/docker/completions.go      | 20 ++++++--------
 cmd/docker/completions_test.go | 49 ++++++++++++++++++++++++++++++++++
 cmd/docker/docker.go           |  6 ++++-
 3 files changed, 62 insertions(+), 13 deletions(-)
 create mode 100644 cmd/docker/completions_test.go

diff --git a/cmd/docker/completions.go b/cmd/docker/completions.go
index 95ee737b42..7c1196d2cf 100644
--- a/cmd/docker/completions.go
+++ b/cmd/docker/completions.go
@@ -1,7 +1,6 @@
 package main
 
 import (
-	"github.com/docker/cli/cli/command/completion"
 	"github.com/docker/cli/cli/context/store"
 	"github.com/spf13/cobra"
 )
@@ -10,18 +9,15 @@ type contextStoreProvider interface {
 	ContextStore() store.Store
 }
 
-func registerCompletionFuncForGlobalFlags(dockerCLI contextStoreProvider, cmd *cobra.Command) error {
-	err := cmd.RegisterFlagCompletionFunc("context", func(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
+func completeContextNames(dockerCLI contextStoreProvider) func(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
+	return func(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
 		names, _ := store.Names(dockerCLI.ContextStore())
 		return names, cobra.ShellCompDirectiveNoFileComp
-	})
-	if err != nil {
-		return err
 	}
-	err = cmd.RegisterFlagCompletionFunc("log-level", completion.FromList("debug", "info", "warn", "error", "fatal"))
-	if err != nil {
-		return err
-	}
-
-	return nil
+}
+
+var logLevels = []string{"debug", "info", "warn", "error", "fatal", "panic"}
+
+func completeLogLevels(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
+	return cobra.FixedCompletions(logLevels, cobra.ShellCompDirectiveNoFileComp)(nil, nil, "")
 }
diff --git a/cmd/docker/completions_test.go b/cmd/docker/completions_test.go
new file mode 100644
index 0000000000..3fa5b35532
--- /dev/null
+++ b/cmd/docker/completions_test.go
@@ -0,0 +1,49 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/docker/cli/cli/context/store"
+	"github.com/spf13/cobra"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
+)
+
+type fakeCLI struct {
+	contextStore store.Store
+}
+
+func (c *fakeCLI) ContextStore() store.Store {
+	return c.contextStore
+}
+
+type fakeContextStore struct {
+	store.Store
+	names []string
+}
+
+func (f fakeContextStore) List() (c []store.Metadata, _ error) {
+	for _, name := range f.names {
+		c = append(c, store.Metadata{Name: name})
+	}
+	return c, nil
+}
+
+func TestCompleteContextNames(t *testing.T) {
+	expectedNames := []string{"context-b", "context-c", "context-a"}
+	cli := &fakeCLI{
+		contextStore: fakeContextStore{
+			names: expectedNames,
+		},
+	}
+
+	values, directives := completeContextNames(cli)(nil, nil, "")
+	assert.Check(t, is.Equal(directives, cobra.ShellCompDirectiveNoFileComp))
+	assert.Check(t, is.DeepEqual(values, expectedNames))
+}
+
+func TestCompleteLogLevels(t *testing.T) {
+	values, directives := completeLogLevels(nil, nil, "")
+	assert.Check(t, is.Equal(directives, cobra.ShellCompDirectiveNoFileComp))
+	assert.Check(t, is.DeepEqual(values, logLevels))
+}
diff --git a/cmd/docker/docker.go b/cmd/docker/docker.go
index 8b15b76f8e..29a3ed5957 100644
--- a/cmd/docker/docker.go
+++ b/cmd/docker/docker.go
@@ -100,7 +100,11 @@ func newDockerCommand(dockerCli *command.DockerCli) *cli.TopLevelCommand {
 	cmd.SetErr(dockerCli.Err())
 
 	opts, helpCmd = cli.SetupRootCommand(cmd)
-	_ = registerCompletionFuncForGlobalFlags(dockerCli, cmd)
+
+	// TODO(thaJeztah): move configuring completion for these flags to where the flags are added.
+	_ = cmd.RegisterFlagCompletionFunc("context", completeContextNames(dockerCli))
+	_ = cmd.RegisterFlagCompletionFunc("log-level", completeLogLevels)
+
 	cmd.Flags().BoolP("version", "v", false, "Print version information and quit")
 	setFlagErrorFunc(dockerCli, cmd)