Establish initial Go application skeleton

internal/cli/root_test.go

@@ -0,0 +1,50 @@
+package cli
+
+import (
+	"bytes"
+	"context"
+	"strings"
+	"testing"
+)
+
+func TestRunHelpLongFlag(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+
+	err := Run(context.Background(), []string{"--help"}, &stdout, &stderr)
+	if err != nil {
+		t.Fatalf("Run() error = %v", err)
+	}
+
+	if !strings.Contains(stdout.String(), "Usage:") {
+		t.Fatalf("help output missing usage:\n%s", stdout.String())
+	}
+}
+
+func TestRunHelpShortFlag(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+
+	err := Run(context.Background(), []string{"-h"}, &stdout, &stderr)
+	if err != nil {
+		t.Fatalf("Run() error = %v", err)
+	}
+
+	if !strings.Contains(stdout.String(), "weatherreporter --help") {
+		t.Fatalf("help output missing root help command:\n%s", stdout.String())
+	}
+}
+
+func TestRunUnknownArgument(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+
+	err := Run(context.Background(), []string{"generate"}, &stdout, &stderr)
+	if err == nil {
+		t.Fatal("Run() error = nil, want unknown argument error")
+	}
+
+	if !strings.Contains(err.Error(), `unknown argument "generate"`) {
+		t.Fatalf("Run() error = %q, want unknown argument message", err.Error())
+	}
+}