Add tests for the command line tool (#7)

* Add basic tests for command line tool

* Add tests to the workflow

Author: moolmanruan

.github/workflows/main.yml

@@ -7,17 +7,17 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
+      - uses: actions/setup-go@v3
+        with:
+          go-version: '^1.19'
+
       - uses: actions/setup-node@v3
         with:
           node-version: '14'
 
       - name: Install Danger JS
         run: npm install -g danger
 
-      - uses: actions/setup-go@v3
-        with:
-          go-version: '^1.19'
-
       - name: Install danger-go
         run: go install github.com/moolmanruan/danger-go/cmd/[email protected] # match version used in build/ci
 
@@ -31,4 +31,17 @@ jobs:
         run: danger-go ci
         working-directory: ./build/ci
     env:
-      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  test:
+    name: Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-go@v3
+        with:
+          go-version: '^1.19'
+
+      - name: Go tests
+        run: go test -v ./...

cmd/danger-go/main.go

@@ -13,17 +13,8 @@ const version = "v0.0.3"
 
 // main entrypoint of the danger-go command
 func main() {
-	// require process (always included) and command/flag
-	if len(os.Args) < 2 {
-		fmt.Println(usage)
-	}
-
-	if argsContain("-V", "--version") {
-		fmt.Printf("danger-go %s\n", version)
-		return
-	}
-	if argsContain("-h", "--help") {
-		fmt.Println(usage)
+	if len(os.Args) <= 1 || argsContain("-h", "--help") {
+		fmt.Print(usage)
 		return
 	}
 
@@ -40,6 +31,8 @@ func main() {
 		}
 	case "runner":
 		runner.Run()
+	case "version":
+		fmt.Printf("danger-go %s\n", version)
 	default:
 		log.Fatalf("invalid sub-command `%s`\n\n%s", command, usage)
 	}
@@ -61,12 +54,12 @@ func argsContain(args ...string) bool {
 const usage = `Usage: danger-go [options] [command]
 
 Options:
-  -V, --version  Output the version number
   -h, --help     Output usage information
 
 Commands:
-  init           Helps you get started with DSL
   ci             Runs DSL on CI
+  local          Runs danger standalone on a repo, useful for git hooks
   pr             Runs your local Dangerfile against an existing GitHub DSL. Will not post on the DSL
   runner         Runs a dangerfile against a DSL passed in via STDIN [You probably don't need this]
-  local          Runs danger standalone on a repo, useful for git hooks`
+  version        Show the version of the application
+`

cmd/danger-go/main_internal_test.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"fmt"
+	"os/exec"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+const cliPkg = "github.com/moolmanruan/danger-go/cmd/danger-go"
+
+func execute(args ...string) (string, error) {
+	cmdArgs := append([]string{"run", cliPkg}, args...)
+	cmd := exec.Command("go", cmdArgs...)
+	res, err := cmd.CombinedOutput()
+	return string(res), err
+}
+
+func TestShowsUsage(t *testing.T) {
+	cc := []struct {
+		name string
+		args []string
+	}{
+		{name: "no args", args: nil},
+		{name: "-h arg", args: []string{"-h"}},
+		{name: "--help arg", args: []string{"--help"}},
+	}
+
+	for _, c := range cc {
+		t.Run(c.name, func(t *testing.T) {
+			res, err := execute(c.args...)
+			require.Nil(t, err)
+			require.Equal(t, usage, res)
+		})
+	}
+}
+
+func TestShowsVersion(t *testing.T) {
+	res, err := execute("version")
+	require.Nil(t, err)
+	require.Equal(t, fmt.Sprintf("danger-go %s\n", version), res)
+}