add tests

Author: aarzilli

_fixtures/pkg1/pkg1.go

@@ -0,0 +1,23 @@
+package pkg1
+
+import (
+	"fmt"
+	"reflect"
+)
+
+type Astruct struct {
+	N int
+}
+
+func (a *Astruct) UnreachableMethod() {
+	fmt.Println("UnreachableMethod")
+}
+
+func (a *Astruct) ReflectMethodByName(name string) {
+	reflect.ValueOf(&Astruct{}).MethodByName(name).Call(nil)
+}
+
+func (a *Astruct) M() {
+	fmt.Println("M", a.N)
+}
+

_fixtures/reachmeth.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"os"
+
+	"github.com/aarzilli/whydeadcode/_fixtures/pkg1"
+)
+
+var f = (*pkg1.Astruct).ReflectMethodByName
+
+func main() {
+	f(&pkg1.Astruct{ 10 }, os.Args[1])
+}

_fixtures/typemethod.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"reflect"
+)
+
+type Bstruct struct {
+	n float64
+}
+
+func (b *Bstruct) M() {
+	fmt.Println("hello world")
+}
+
+func F(name string) {
+	mmeth, _ := reflect.TypeOf(&Bstruct{}).MethodByName(name)
+	mmeth.Func.Call(nil)
+}
+
+func main() {
+	F(os.Args[1])
+}

_fixtures/valuemethod.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"reflect"
+)
+
+type Bstruct struct {
+	n float64
+}
+
+func (b *Bstruct) M() {
+	fmt.Println("hello world")
+}
+
+func F(name string) {
+	reflect.ValueOf(&Bstruct{ 2.0 }).MethodByName(name).Call(nil)
+}
+
+func main() {
+	F(os.Args[1])
+}

main_test.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+)
+
+func TestWhydeadcode(t *testing.T) {
+	for _, c := range []struct {
+		fixtureName string
+		tgt         Path
+	}{
+		{"valuemethod", Path{"main.F", "main.main"}},
+		{"typemethod", Path{"main.F", "main.main"}},
+		{"reachmeth", Path{"github.com/aarzilli/whydeadcode/_fixtures/pkg1.(*Astruct).ReflectMethodByName", "github.com/aarzilli/whydeadcode/_fixtures/pkg1.(*Astruct).ReflectMethodByName·f", "main.f", "main.main"}},
+	} {
+		t.Run(c.fixtureName, func(t *testing.T) {
+			paths, _ := Whydeadcode(buildFixture(t, c.fixtureName))
+			t.Logf("%q -> %q", c.fixtureName, paths[0])
+			if len(paths[0]) < len(c.tgt) {
+				t.Error("output path not long enough")
+			}
+			for i := range c.tgt {
+				if c.tgt[i] != paths[0][i] {
+					t.Errorf("mismatch at index %d (expected %q got %q)", i, c.tgt[i], paths[0][i])
+					break
+				}
+			}
+		})
+	}
+}
+
+func buildFixture(t *testing.T, name string) io.Reader {
+	t.Helper()
+	cmd := exec.Command("go", "build", "-o", "_debug", "-ldflags=-dumpdep", filepath.Join("_fixtures", name)+".go")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("compilation failed for %q: %v", name, err)
+	}
+	os.Remove("_debug")
+	return bytes.NewReader(out)
+}