Fix cmp tests (#31)

A prior commit changes the tests to run in parallel, but due to shadowing
bug, would only run the last test case. Fix this by creating an explicit
scoping of the variable for each iteration of the loop.

Also perform other cleanups.

1 files changed, 46 insertions, 81 deletions

diff --git a/cmp/compare_test.go b/cmp/compare_test.go
index 2db0236..a0c003e 100644
--- a/cmp/compare_test.go
+++ b/cmp/compare_test.go
@@ -18,53 +18,17 @@ import (
 	"sync"
 	"testing"
 	"time"
-	"unicode"
-	"unicode/utf8"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 	pb "github.com/google/go-cmp/cmp/internal/testprotos"
 	ts "github.com/google/go-cmp/cmp/internal/teststructs"
 )
 
 var now = time.Now()
-var boolType = reflect.TypeOf(true)
-var mutexType = reflect.TypeOf(sync.Mutex{})
 
 func intPtr(n int) *int { return &n }
 
-func equalRegexp(x, y *regexp.Regexp) bool {
-	if x == nil || y == nil {
-		return x == nil && y == nil
-	}
-	return x.String() == y.String()
-}
-
-func IgnoreUnexported(typs ...interface{}) cmp.Option {
-	m := make(map[reflect.Type]bool)
-	for _, typ := range typs {
-		t := reflect.TypeOf(typ)
-		if t.Kind() != reflect.Struct {
-			panic(fmt.Sprintf("invalid struct type: %T", typ))
-		}
-		m[t] = true
-	}
-	return cmp.FilterPath(func(p cmp.Path) bool {
-		if len(p) < 2 {
-			return false
-		}
-		sf, ok := p[len(p)-1].(cmp.StructField)
-		if !ok {
-			return false
-		}
-		return m[p[len(p)-2].Type()] && !isExported(sf.Name())
-	}, cmp.Ignore())
-}
-
-func isExported(id string) bool {
-	r, _ := utf8.DecodeRuneInString(id)
-	return unicode.IsUpper(r)
-}
-
 type test struct {
 	label     string       // Test description
 	x, y      interface{}  // Input values to compare
@@ -79,13 +43,13 @@ func TestDiff(t *testing.T) {
 	tests = append(tests, transformerTests()...)
 	tests = append(tests, embeddedTests()...)
 	tests = append(tests, methodTests()...)
-	tests = append(tests, formatTests()...)
 	tests = append(tests, project1Tests()...)
 	tests = append(tests, project2Tests()...)
 	tests = append(tests, project3Tests()...)
 	tests = append(tests, project4Tests()...)
 
 	for _, tt := range tests {
+		tt := tt
 		tRunParallel(t, tt.label, func(t *testing.T) {
 			var gotDiff, gotPanic string
 			func() {
@@ -248,12 +212,22 @@ func comparerTests() []test {
 		label: label,
 		x:     []*regexp.Regexp{nil, regexp.MustCompile("a*b*c*")},
 		y:     []*regexp.Regexp{nil, regexp.MustCompile("a*b*c*")},
-		opts:  []cmp.Option{cmp.Comparer(equalRegexp)},
+		opts: []cmp.Option{cmp.Comparer(func(x, y *regexp.Regexp) bool {
+			if x == nil || y == nil {
+				return x == nil && y == nil
+			}
+			return x.String() == y.String()
+		})},
 	}, {
 		label: label,
 		x:     []*regexp.Regexp{nil, regexp.MustCompile("a*b*c*")},
 		y:     []*regexp.Regexp{nil, regexp.MustCompile("a*b*d*")},
-		opts:  []cmp.Option{cmp.Comparer(equalRegexp)},
+		opts: []cmp.Option{cmp.Comparer(func(x, y *regexp.Regexp) bool {
+			if x == nil || y == nil {
+				return x == nil && y == nil
+			}
+			return x.String() == y.String()
+		})},
 		wantDiff: `
 {[]*regexp.Regexp}[1]:
 	-: "a*b*c*"
@@ -318,6 +292,14 @@ root:
 	+: [16]uint8{0x92, 0xeb, 0x5f, 0xfe, 0xe6, 0xae, 0x2f, 0xec, 0x3a, 0xd7, 0x1c, 0x77, 0x75, 0x31, 0x57, 0x8f}`,
 	}, {
 		label: label,
+		x:     new(fmt.Stringer),
+		y:     nil,
+		wantDiff: `
+:
+	-: &<nil>
+	+: <non-existent>`,
+	}, {
+		label: label,
 		x:     make([]int, 1000),
 		y:     make([]int, 1000),
 		opts: []cmp.Option{
@@ -542,7 +524,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructA{},
 		y:     ts.ParentStructA{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructA{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructA{}),
 		},
 	}, {
 		label: label + "ParentStructA",
@@ -578,7 +560,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructB{},
 		y:     ts.ParentStructB{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructB{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructB{}),
 		},
 		wantPanic: "cannot handle unexported field",
 	}, {
@@ -586,8 +568,8 @@ func embeddedTests() []test {
 		x:     ts.ParentStructB{},
 		y:     ts.ParentStructB{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructB{}),
-			IgnoreUnexported(ts.PublicStruct{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructB{}),
+			cmpopts.IgnoreUnexported(ts.PublicStruct{}),
 		},
 	}, {
 		label: label + "ParentStructB",
@@ -628,7 +610,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructC{},
 		y:     ts.ParentStructC{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructC{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructC{}),
 		},
 	}, {
 		label: label + "ParentStructC",
@@ -670,7 +652,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructD{},
 		y:     ts.ParentStructD{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructD{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructD{}),
 		},
 		wantPanic: "cannot handle unexported field",
 	}, {
@@ -678,8 +660,8 @@ func embeddedTests() []test {
 		x:     ts.ParentStructD{},
 		y:     ts.ParentStructD{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructD{}),
-			IgnoreUnexported(ts.PublicStruct{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructD{}),
+			cmpopts.IgnoreUnexported(ts.PublicStruct{}),
 		},
 	}, {
 		label: label + "ParentStructD",
@@ -721,7 +703,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructE{},
 		y:     ts.ParentStructE{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructE{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructE{}),
 		},
 		wantPanic: "cannot handle unexported field",
 	}, {
@@ -729,8 +711,8 @@ func embeddedTests() []test {
 		x:     ts.ParentStructE{},
 		y:     ts.ParentStructE{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructE{}),
-			IgnoreUnexported(ts.PublicStruct{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructE{}),
+			cmpopts.IgnoreUnexported(ts.PublicStruct{}),
 		},
 	}, {
 		label: label + "ParentStructE",
@@ -780,7 +762,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructF{},
 		y:     ts.ParentStructF{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructF{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructF{}),
 		},
 		wantPanic: "cannot handle unexported field",
 	}, {
@@ -788,8 +770,8 @@ func embeddedTests() []test {
 		x:     ts.ParentStructF{},
 		y:     ts.ParentStructF{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructF{}),
-			IgnoreUnexported(ts.PublicStruct{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructF{}),
+			cmpopts.IgnoreUnexported(ts.PublicStruct{}),
 		},
 	}, {
 		label: label + "ParentStructF",
@@ -850,7 +832,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructG{},
 		y:     ts.ParentStructG{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructG{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructG{}),
 		},
 	}, {
 		label: label + "ParentStructG",
@@ -895,7 +877,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructH{},
 		y:     ts.ParentStructH{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructH{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructH{}),
 		},
 	}, {
 		label: label + "ParentStructH",
@@ -936,14 +918,14 @@ func embeddedTests() []test {
 		x:     ts.ParentStructI{},
 		y:     ts.ParentStructI{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructI{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructI{}),
 		},
 	}, {
 		label: label + "ParentStructI",
 		x:     createStructI(0),
 		y:     createStructI(0),
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructI{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructI{}),
 		},
 		wantPanic: "cannot handle unexported field",
 	}, {
@@ -951,7 +933,7 @@ func embeddedTests() []test {
 		x:     createStructI(0),
 		y:     createStructI(0),
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructI{}, ts.PublicStruct{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructI{}, ts.PublicStruct{}),
 		},
 	}, {
 		label: label + "ParentStructI",
@@ -998,7 +980,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructJ{},
 		y:     ts.ParentStructJ{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructJ{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructJ{}),
 		},
 		wantPanic: "cannot handle unexported field",
 	}, {
@@ -1006,7 +988,7 @@ func embeddedTests() []test {
 		x:     ts.ParentStructJ{},
 		y:     ts.ParentStructJ{},
 		opts: []cmp.Option{
-			IgnoreUnexported(ts.ParentStructJ{}, ts.PublicStruct{}),
+			cmpopts.IgnoreUnexported(ts.ParentStructJ{}, ts.PublicStruct{}),
 		},
 	}, {
 		label: label + "ParentStructJ",
@@ -1075,7 +1057,7 @@ func methodTests() []test {
 		if m, ok := reflect.PtrTo(t).MethodByName("Equal"); ok {
 			tf := m.Func.Type()
 			return !tf.IsVariadic() && tf.NumIn() == 2 && tf.NumOut() == 1 &&
-				tf.In(0).AssignableTo(tf.In(1)) && tf.Out(0) == boolType
+				tf.In(0).AssignableTo(tf.In(1)) && tf.Out(0) == reflect.TypeOf(true)
 		}
 		return false
 	}, cmp.Transformer("Ref", func(x interface{}) interface{} {
@@ -1362,25 +1344,10 @@ func methodTests() []test {
 	}}
 }
 
-func formatTests() []test {
-	const label = "Format/"
-	return []test{
-		{
-			label: label + "NilStringer",
-			x:     new(fmt.Stringer),
-			y:     nil,
-			wantDiff: `
-:
-	-: &<nil>
-	+: <non-existent>`,
-		},
-	}
-}
-
 func project1Tests() []test {
 	const label = "Project1"
 
-	ignoreUnexported := IgnoreUnexported(
+	ignoreUnexported := cmpopts.IgnoreUnexported(
 		ts.EagleImmutable{},
 		ts.DreamerImmutable{},
 		ts.SlapImmutable{},
@@ -1636,9 +1603,7 @@ func project3Tests() []test {
 
 	allowVisibility := cmp.AllowUnexported(ts.Dirt{})
 
-	ignoreLocker := cmp.FilterPath(func(p cmp.Path) bool {
-		return len(p) > 0 && p[len(p)-1].Type() == mutexType
-	}, cmp.Ignore())
+	ignoreLocker := cmpopts.IgnoreInterfaces(struct{ sync.Locker }{})
 
 	transformProtos := cmp.Transformer("", func(x pb.Dirt) *pb.Dirt {
 		return &x