Test version command

Signed-off-by: Max Proske <max@mproske.com>

cmd/compose/version_test.go

@@ -0,0 +1,76 @@
+/*
+   Copyright 2025 Docker Compose CLI authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package compose
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/docker/cli/cli/streams"
+	"github.com/docker/compose/v2/internal"
+	"github.com/docker/compose/v2/pkg/mocks"
+	"go.uber.org/mock/gomock"
+	"gotest.tools/v3/assert"
+)
+
+func TestVersionCommand(t *testing.T) {
+	originalVersion := internal.Version
+	defer func() {
+		internal.Version = originalVersion
+	}()
+	internal.Version = "v9.9.9-test"
+
+	tests := []struct {
+		name string
+		args []string
+		want string
+	}{
+		{
+			name: "default",
+			args: []string{},
+			want: "Docker Compose version v9.9.9-test\n",
+		},
+		{
+			name: "short flag",
+			args: []string{"--short"},
+			want: "9.9.9-test\n",
+		},
+		{
+			name: "json flag",
+			args: []string{"--format", "json"},
+			want: `{"version":"v9.9.9-test"}` + "\n",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+
+			buf := new(bytes.Buffer)
+			cli := mocks.NewMockCli(ctrl)
+			cli.EXPECT().Out().Return(streams.NewOut(buf)).AnyTimes()
+
+			cmd := versionCommand(cli)
+			cmd.SetArgs(test.args)
+			err := cmd.Execute()
+			assert.NilError(t, err)
+
+			assert.Equal(t, test.want, buf.String())
+		})
+	}
+}