Change cmg -testify flag to use assert.TestingT (#639)

When the -testify flag is used, mock constructors now accept
assert.TestingT instead of *testing.T, providing better flexibility
for testing with custom test harnesses.

Also update the minimum Go version requirement from 1.21 to 1.24
in GitHub Actions workflows and README.

Author: douglaswth

.github/workflows/ci.yaml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: actions/setup-go@v5
         with:
-          go-version: "1.21"
+          go-version: "1.24"
       - name: tests
         run: scripts/cibuild
       - name: Upload coverage to Codecov

.github/workflows/integration.yaml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: actions/setup-go@v5
         with:
-          go-version: "1.21"
+          go-version: "1.24"
       - name: tests
         run: |
           check_service_health() {

README.md

@@ -78,7 +78,7 @@ debug and operate microservices using Clue's instrumentation capabilities.
 
 ## Installation
 
-Clue requires Go 1.21 or later. Install the packages required for your
+Clue requires Go 1.24 or later. Install the packages required for your
 application using `go get`, for example:
 
 ```bash

go.work.sum

@@ -60,12 +60,14 @@ var (
 // If testify is true, it uses github.com/stretchr/testify for assertions.
 func NewMocks(prefix string, p parse.Package, interfaces []parse.Interface, toolVersionFunc ToolVersionFunc, testify bool) Mocks {
 	var (
-		stdImports = importMap{"testing": newImport("testing")}
+		stdImports = make(importMap)
 		extImports = importMap{"mock": newImport("goa.design/clue/mock")}
 		intImports = make(importMap)
 	)
 	if testify {
 		extImports["assert"] = newImport("github.com/stretchr/testify/assert")
+	} else {
+		stdImports["testing"] = newImport("testing")
 	}
 
 	var (

mock/cmd/cmg/pkg/generate/_tests/testify/mocks/testify.go

@@ -9,10 +9,14 @@ import (
 {{- range .StdImports }}
 	{{ if .Alias }}{{ .Alias }} {{ end }}"{{ .PkgPath }}"
 {{- end }}
-{{ range .ExtImports }}
+{{- if and (gt (len .StdImports) 0) (or (gt (len .ExtImports) 0) (gt (len .IntImports) 0)) }}
+{{ end }}
+{{- range .ExtImports }}
 	{{ if .Alias }}{{ .Alias }} {{ end }}"{{ .PkgPath }}"
 {{- end }}
-{{ range .IntImports }}
+{{- if and (gt (len .ExtImports) 0) (gt (len .IntImports) 0) }}
+{{ end }}
+{{- range .IntImports }}
 	{{ if .Alias }}{{ .Alias }} {{ end }}"{{ .PkgPath }}"
 {{- end }}
 )
@@ -40,7 +44,7 @@ type (
 {{- range $index, $interface := .Interfaces }}
 {{- if ge $index 1 }}
 {{ end }}
-func {{ .Constructor }}{{ .TypeParameters }}(t *testing.T) *{{ .Name }}{{ .TypeParameterVars }} {
+func {{ .Constructor }}{{ .TypeParameters }}(t {{ if $testify }}assert.TestingT{{ else }}*testing.T{{ end }}) *{{ .Name }}{{ .TypeParameterVars }} {
 	var (
 		{{ .Var | printf ($import.AliasOrPkgName | .ConstructorFmt) }} = &{{ .Name }}{{ .TypeParameterVars }}{mock.New(), {{ if $testify }}assert.New(t){{ else }}t{{ end }}}
 		_ {{ $import.AliasOrPkgName }}.{{ .Name }}{{ .TypeParameterVars }} = m