Move e2e test on version command to unit tests

* Refactor a little version command

Signed-off-by: Silvin Lubecki <silvin.lubecki@docker.com>

cli/command/system/version_test.go

@@ -0,0 +1,55 @@
+package system
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/docker/cli/cli/config/configfile"
+	"github.com/docker/cli/internal/test"
+	"github.com/docker/docker/api"
+	"github.com/docker/docker/api/types"
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/net/context"
+)
+
+func TestVersionWithoutServer(t *testing.T) {
+	cli := test.NewFakeCli(&fakeClient{
+		serverVersion: func(ctx context.Context) (types.Version, error) {
+			return types.Version{}, fmt.Errorf("no server")
+		},
+	})
+	cmd := NewVersionCommand(cli)
+	cmd.SetOutput(cli.Err())
+	assert.Error(t, cmd.Execute())
+	assert.Contains(t, cleanTabs(cli.OutBuffer().String()), "Client:")
+	assert.NotContains(t, cleanTabs(cli.OutBuffer().String()), "Server:")
+}
+
+func fakeServerVersion(ctx context.Context) (types.Version, error) {
+	return types.Version{
+		Version:    "docker-dev",
+		APIVersion: api.DefaultVersion,
+	}, nil
+}
+
+func TestVersionWithDefaultOrchestrator(t *testing.T) {
+	cli := test.NewFakeCli(&fakeClient{serverVersion: fakeServerVersion})
+	cmd := NewVersionCommand(cli)
+	assert.NoError(t, cmd.Execute())
+	assert.Contains(t, cleanTabs(cli.OutBuffer().String()), "Orchestrator: swarm")
+}
+
+func TestVersionWithOverridenOrchestrator(t *testing.T) {
+	cli := test.NewFakeCli(&fakeClient{serverVersion: fakeServerVersion})
+	config := configfile.New("configfile")
+	config.Orchestrator = "Kubernetes"
+	cli.SetConfigFile(config)
+	cmd := NewVersionCommand(cli)
+	assert.NoError(t, cmd.Execute())
+	assert.Contains(t, cleanTabs(cli.OutBuffer().String()), "Orchestrator: kubernetes")
+}
+
+func cleanTabs(line string) string {
+	return strings.Join(strings.Fields(line), " ")
+}