refactor: add generate cmd test

cmd/templ/fmtcmd/main_test.go

@@ -63,9 +63,11 @@ func TestFormat(t *testing.T) {
 		defer tp.cleanup()
 		stdin := strings.NewReader(tp.testFiles["a.templ"].input)
 		stdout := new(strings.Builder)
-		Run(log, stdin, stdout, Arguments{
+		if err = Run(log, stdin, stdout, Arguments{
 			ToStdout: true,
-		})
+		}); err != nil {
+			t.Fatalf("failed to run format command: %v", err)
+		}
 		if diff := cmp.Diff(tp.testFiles["a.templ"].expected, stdout.String()); diff != "" {
 			t.Error(diff)
 		}
@@ -77,12 +79,14 @@ func TestFormat(t *testing.T) {
 		}
 		defer tp.cleanup()
 		stdout := new(strings.Builder)
-		Run(log, nil, stdout, Arguments{
+		if err = Run(log, nil, stdout, Arguments{
 			ToStdout: true,
 			Files: []string{
 				tp.testFiles["a.templ"].name,
 			},
-		})
+		}); err != nil {
+			t.Fatalf("failed to run format command: %v", err)
+		}
 		if diff := cmp.Diff(tp.testFiles["a.templ"].expected, stdout.String()); diff != "" {
 			t.Error(diff)
 		}
@@ -93,11 +97,13 @@ func TestFormat(t *testing.T) {
 			t.Fatalf("failed to setup project dir: %v", err)
 		}
 		defer tp.cleanup()
-		Run(log, nil, nil, Arguments{
+		if err = Run(log, nil, nil, Arguments{
 			Files: []string{
 				tp.testFiles["a.templ"].name,
 			},
-		})
+		}); err != nil {
+			t.Fatalf("failed to run format command: %v", err)
+		}
 		data, err := os.ReadFile(tp.testFiles["a.templ"].name)
 		if err != nil {
 			t.Fatalf("failed to read file: %v", err)

cmd/templ/generatecmd/main_test.go

@@ -0,0 +1,44 @@
+package generatecmd
+
+import (
+	"context"
+	"io"
+	"log/slog"
+	"os"
+	"path"
+	"testing"
+
+	"github.com/a-h/templ/cmd/templ/testproject"
+)
+
+func TestGenerate(t *testing.T) {
+	log := slog.New(slog.NewJSONHandler(io.Discard, nil))
+	t.Run("can generate a file in place", func(t *testing.T) {
+		// templ generate -f templates.templ
+		dir, err := testproject.Create("github.com/a-h/templ/cmd/templ/testproject")
+		if err != nil {
+			t.Fatalf("failed to create test project: %v", err)
+		}
+		defer os.RemoveAll(dir)
+
+		// Delete the templates_templ.go file to ensure it is generated.
+		err = os.Remove(path.Join(dir, "templates_templ.go"))
+		if err != nil {
+			t.Fatalf("failed to remove templates_templ.go: %v", err)
+		}
+
+		// Run the generate command.
+		err = Run(context.Background(), log, Arguments{
+			FileName: path.Join(dir, "templates.templ"),
+		})
+		if err != nil {
+			t.Fatalf("failed to run generate command: %v", err)
+		}
+
+		// Check the templates_templ.go file was created.
+		_, err = os.Stat(path.Join(dir, "templates_templ.go"))
+		if err != nil {
+			t.Fatalf("templates_templ.go was not created: %v", err)
+		}
+	})
+}