add integration test to validate type aliases are treated correctly

Signed-off-by: Joe Fitzgerald <joe@wearemomentum.ai>

fixtures/dup_packages/go.mod

@@ -1,3 +1,3 @@
 module github.com/maxbrunsfeld/counterfeiter/v6/fixtures/dup_packages
 
-go 1.12
+go 1.22

fixtures/type_aliases/extra/m.go

@@ -0,0 +1,5 @@
+package extra // import "github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases/extra"
+
+import "github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases/extra/primitive"
+
+type M = primitive.M

fixtures/type_aliases/extra/primitive/m.go

@@ -0,0 +1,3 @@
+package primitive // import "github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases/primitive"
+
+type M map[string]interface{}

fixtures/type_aliases/go.mod

@@ -0,0 +1,3 @@
+module github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases
+
+go 1.22

fixtures/type_aliases/interface.go

@@ -0,0 +1,14 @@
+package type_aliases // import "github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases"
+
+import (
+	"context"
+
+	"github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases/extra"
+)
+
+//go:generate go run github.com/maxbrunsfeld/counterfeiter/v6 -generate
+
+//counterfeiter:generate . WithAliasedType
+type WithAliasedType interface {
+	FindExample(ctx context.Context, filter extra.M) ([]string, error)
+}

integration/roundtrip_test.go

@@ -121,6 +121,25 @@ func runTests(t *testing.T, when spec.G, it spec.S) {
 		})
 	})
 
+	when("generating interfaces using type aliases", func() {
+		it.Before(func() {
+			relativeDir = filepath.Join(relativeDir, "type_aliases")
+			copyDirFunc()
+		})
+		it("imports the aliased type, not the underlying type", func() {
+			cache := &generator.FakeCache{}
+			pkgPath := "github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases"
+			interfaceName := "WithAliasedType"
+			fakePackageName := "type_aliasesfakes"
+			f, err := generator.NewFake(generator.InterfaceOrFunction, interfaceName, pkgPath, "Fake"+interfaceName, fakePackageName, "", baseDir, cache)
+			Expect(err).NotTo(HaveOccurred())
+			b, err := f.Generate(false)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(string(b)).NotTo(ContainSubstring("primitive"))
+			Expect(string(b)).To(ContainSubstring(`"github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases/extra"`))
+		})
+	})
+
 	when(name, func() {
 		t := func(interfaceName string, filename string, subDir string, files ...string) {
 			when("working with "+filename, func() {