fix(cli): address remaining review feedback

Author: aryeko

cmd/modkit/main_test.go

@@ -1,6 +1,9 @@
 package main
 
-import "testing"
+import (
+	"os"
+	"testing"
+)
 
 func TestRunHelp(t *testing.T) {
 	if code := run([]string{"modkit", "--help"}); code != 0 {
@@ -16,7 +19,11 @@ func TestRunInvalidCommand(t *testing.T) {
 
 func TestMainInvokesExit(t *testing.T) {
 	orig := osExit
-	t.Cleanup(func() { osExit = orig })
+	origArgs := os.Args
+	t.Cleanup(func() {
+		osExit = orig
+		os.Args = origArgs
+	})
 
 	called := false
 	got := -1
@@ -25,12 +32,13 @@ func TestMainInvokesExit(t *testing.T) {
 		got = code
 	}
 
+	os.Args = []string{"modkit", "--help"}
 	main()
 
 	if !called {
 		t.Fatal("expected main to call osExit")
 	}
 	if got != 0 {
-		t.Fatalf("expected exit code 0 from test binary args, got %d", got)
+		t.Fatalf("expected exit code 0, got %d", got)
 	}
 }

docs/specs/design-cli-tooling.md

@@ -51,15 +51,16 @@ Run:
 $ cd my-service
 $ modkit new module users
 Created internal/modules/users/module.go
-Created internal/modules/users/module_test.go
 ```
 
 ### 4.3. Adding a Provider
 
 ```bash
 $ modkit new provider service --module users
 Created internal/modules/users/service.go
-Updated internal/modules/users/module.go (registered provider)
+TODO: Register provider in internal/modules/users/module.go:
+  Token: "users.service"
+  Build: func(r module.Resolver) (any, error) { return NewServiceService(), nil }
 ```
 
 ## 5. Implementation Details

internal/cli/ast/modify.go

@@ -7,13 +7,20 @@ import (
 	"go/token"
 	"os"
 	"path/filepath"
+	"regexp"
 
 	"github.com/dave/dst"
 	"github.com/dave/dst/decorator"
 )
 
+var providerTokenPattern = regexp.MustCompile(`^[A-Za-z0-9_]+\.[A-Za-z0-9_]+$`)
+
 // AddProvider registers a new provider in the module definition.
 func AddProvider(filePath, providerToken, buildFunc string) error {
+	if !providerTokenPattern.MatchString(providerToken) {
+		return fmt.Errorf("provider token must be in module.component format: %q", providerToken)
+	}
+
 	fset := token.NewFileSet()
 	f, err := decorator.ParseFile(fset, filePath, nil, parser.ParseComments)
 	if err != nil {

internal/cli/ast/modify_test.go

@@ -93,3 +93,28 @@ type Module struct{}
 		t.Fatal("expected error when Definition method is missing")
 	}
 }
+
+func TestAddProviderInvalidToken(t *testing.T) {
+	tmp := t.TempDir()
+	file := filepath.Join(tmp, "module.go")
+	content := `package users
+
+import "github.com/go-modkit/modkit/modkit/module"
+
+type Module struct{}
+
+func (m *Module) Definition() module.ModuleDef {
+	return module.ModuleDef{
+		Name: "users",
+		Providers: []module.ProviderDef{},
+	}
+}
+`
+	if err := os.WriteFile(file, []byte(content), 0o600); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := AddProvider(file, "bad token", "buildAuth"); err == nil {
+		t.Fatal("expected error for invalid token format")
+	}
+}

internal/cli/cmd/new_provider_test.go

@@ -11,21 +11,37 @@ import (
 	"github.com/spf13/cobra"
 )
 
-func captureStdout(t *testing.T, fn func() error) (string, error) {
+func captureStdout(t *testing.T, fn func() error) (out string, errRun error) {
 	t.Helper()
 	orig := os.Stdout
 	r, w, err := os.Pipe()
 	if err != nil {
 		return "", err
 	}
+
 	os.Stdout = w
-	errRun := fn()
-	_ = w.Close()
-	os.Stdout = orig
-	var buf bytes.Buffer
-	_, _ = io.Copy(&buf, r)
-	_ = r.Close()
-	return buf.String(), errRun
+	var panicV any
+
+	defer func() {
+		os.Stdout = orig
+		_ = w.Close()
+		var buf bytes.Buffer
+		_, _ = io.Copy(&buf, r)
+		out = buf.String()
+		_ = r.Close()
+		if panicV != nil {
+			panic(panicV)
+		}
+	}()
+
+	func() {
+		defer func() {
+			panicV = recover()
+		}()
+		errRun = fn()
+	}()
+
+	return out, errRun
 }
 
 func TestCreateNewProvider(t *testing.T) {