Add initial unit tests

cmd/testdata/TestVersion.golden

@@ -0,0 +1,5 @@
+airshipadm: v0.1.0
+golang    : go1.12
+kubernetes: v1.12.6
+helm      : TODO
+argo      : TODO

cmd/testdata/golden/TestVersion.golden

@@ -0,0 +1,5 @@
+airshipadm: v0.1.0
+golang    : go1.12
+kubernetes: v1.12.6
+helm      : TODO
+argo      : TODO

cmd/version_test.go

@@ -0,0 +1,15 @@
+package cmd_test
+
+import (
+	"testing"
+
+	"github.com/ian-howell/airshipadm/internal/test"
+)
+
+func TestVersion(t *testing.T) {
+	tests := []test.CmdTest{{
+		Name:    "version",
+		Command: "version",
+	}}
+	test.RunCmdTests(t, tests)
+}

internal/test/utilities.go

@@ -0,0 +1,62 @@
+package test
+
+import (
+	"bytes"
+	"flag"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/ian-howell/airshipadm/cmd"
+)
+
+// UpdateGolden writes out the golden files with the latest values, rather than failing the test.
+var updateGolden = flag.Bool("update", false, "update golden files")
+
+const goldenFileDir = "testdata/golden"
+
+type CmdTest struct {
+	Name    string
+	Command string
+}
+
+func RunCmdTests(t *testing.T, tests []CmdTest) {
+	t.Helper()
+
+	for _, test := range tests {
+		executeCmd(t, test.Command)
+	}
+}
+
+func executeCmd(t *testing.T, command string) {
+	var actual bytes.Buffer
+	rootCmd := cmd.NewRootCmd(&actual)
+
+	// TODO(howell): switch to shellwords (or similar)
+	args := strings.Fields(command)
+	rootCmd.SetArgs(args)
+
+	rootCmd.Execute()
+
+	goldenFilePath := filepath.Join(goldenFileDir, filepath.FromSlash(t.Name())+".golden")
+	if *updateGolden {
+		t.Logf("updating golden file: %s", goldenFilePath)
+		if err := ioutil.WriteFile(goldenFilePath, actual.Bytes(), 0644); err != nil {
+			t.Fatalf("failed to update golden file: %s", err)
+		}
+		return
+	}
+	golden, err := ioutil.ReadFile(goldenFilePath)
+	if err != nil {
+		t.Fatalf("failed while reading golden file: %s", err)
+	}
+	if !bytes.Equal(actual.Bytes(), golden) {
+		errFmt := "output does not match golden file: %s\nEXPECTED:\n%s\nGOT:\n%s"
+		t.Errorf(errFmt, goldenFilePath, string(golden), actual.String)
+	}
+}
+
+func normalize(in []byte) []byte {
+	return bytes.Replace(in, []byte("\r\n"), []byte("\n"), -1)
+}