diff --git a/format_test.go b/format_test.go
index c2eef5f0..38ce6f7a 100644
--- a/format_test.go
+++ b/format_test.go
@@ -27,7 +27,7 @@ func TestFormatNew(t *testing.T) {
 		"%+v",
 		"error\n" +
 			"github.com/pkg/errors.TestFormatNew\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:26",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:26",
 	}, {
 		New("error"),
 		"%q",
@@ -57,7 +57,7 @@ func TestFormatErrorf(t *testing.T) {
 		"%+v",
 		"error\n" +
 			"github.com/pkg/errors.TestFormatErrorf\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:56",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:56",
 	}}
 
 	for i, tt := range tests {
@@ -83,7 +83,7 @@ func TestFormatWrap(t *testing.T) {
 		"%+v",
 		"error\n" +
 			"github.com/pkg/errors.TestFormatWrap\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:82",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:82",
 	}, {
 		Wrap(io.EOF, "error"),
 		"%s",
@@ -98,14 +98,14 @@ func TestFormatWrap(t *testing.T) {
 		"EOF\n" +
 			"error\n" +
 			"github.com/pkg/errors.TestFormatWrap\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:96",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:96",
 	}, {
 		Wrap(Wrap(io.EOF, "error1"), "error2"),
 		"%+v",
 		"EOF\n" +
 			"error1\n" +
 			"github.com/pkg/errors.TestFormatWrap\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:103\n",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:103\n",
 	}, {
 		Wrap(New("error with space"), "context"),
 		"%q",
@@ -136,7 +136,7 @@ func TestFormatWrapf(t *testing.T) {
 		"EOF\n" +
 			"error2\n" +
 			"github.com/pkg/errors.TestFormatWrapf\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:134",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:134",
 	}, {
 		Wrapf(New("error"), "error%d", 2),
 		"%s",
@@ -150,7 +150,7 @@ func TestFormatWrapf(t *testing.T) {
 		"%+v",
 		"error\n" +
 			"github.com/pkg/errors.TestFormatWrapf\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:149",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:149",
 	}}
 
 	for i, tt := range tests {
@@ -176,7 +176,7 @@ func TestFormatWithStack(t *testing.T) {
 		"%+v",
 		[]string{"EOF",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:175"},
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:175"},
 	}, {
 		WithStack(New("error")),
 		"%s",
@@ -190,36 +190,36 @@ func TestFormatWithStack(t *testing.T) {
 		"%+v",
 		[]string{"error",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:189",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:189",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:189"},
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:189"},
 	}, {
 		WithStack(WithStack(io.EOF)),
 		"%+v",
 		[]string{"EOF",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:197",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:197",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:197"},
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:197"},
 	}, {
 		WithStack(WithStack(Wrapf(io.EOF, "message"))),
 		"%+v",
 		[]string{"EOF",
 			"message",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:205",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:205",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:205",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:205",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:205"},
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:205"},
 	}, {
 		WithStack(Errorf("error%d", 1)),
 		"%+v",
 		[]string{"error1",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:216",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:216",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:216"},
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:216"},
 	}}
 
 	for i, tt := range tests {
@@ -246,7 +246,7 @@ func TestFormatWithMessage(t *testing.T) {
 		[]string{
 			"error",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:244",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:244",
 			"error2"},
 	}, {
 		WithMessage(io.EOF, "addition1"),
@@ -273,13 +273,13 @@ func TestFormatWithMessage(t *testing.T) {
 		"%+v",
 		[]string{"EOF", "error1", "error2",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:272"},
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:272"},
 	}, {
 		WithMessage(Errorf("error%d", 1), "error2"),
 		"%+v",
 		[]string{"error1",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:278",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:278",
 			"error2"},
 	}, {
 		WithMessage(WithStack(io.EOF), "error"),
@@ -287,7 +287,7 @@ func TestFormatWithMessage(t *testing.T) {
 		[]string{
 			"EOF",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:285",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:285",
 			"error"},
 	}, {
 		WithMessage(Wrap(WithStack(io.EOF), "inside-error"), "outside-error"),
@@ -295,10 +295,10 @@ func TestFormatWithMessage(t *testing.T) {
 		[]string{
 			"EOF",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:293",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:293",
 			"inside-error",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:293",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:293",
 			"outside-error"},
 	}}
 
@@ -315,11 +315,11 @@ func TestFormatGeneric(t *testing.T) {
 		{New("new-error"), []string{
 			"new-error",
 			"github.com/pkg/errors.TestFormatGeneric\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:315"},
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:315"},
 		}, {Errorf("errorf-error"), []string{
 			"errorf-error",
 			"github.com/pkg/errors.TestFormatGeneric\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:319"},
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/format_test.go:319"},
 		}, {errors.New("errors-new-error"), []string{
 			"errors-new-error"},
 		},
@@ -333,21 +333,21 @@ func TestFormatGeneric(t *testing.T) {
 			func(err error) error { return WithStack(err) },
 			[]string{
 				"github.com/pkg/errors.(func·002|TestFormatGeneric.func2)\n\t" +
-					".+/github.com/pkg/errors/format_test.go:333",
+					".+/github.com/pkg/errors(@v[^/]+)?/format_test.go:333",
 			},
 		}, {
 			func(err error) error { return Wrap(err, "wrap-error") },
 			[]string{
 				"wrap-error",
 				"github.com/pkg/errors.(func·003|TestFormatGeneric.func3)\n\t" +
-					".+/github.com/pkg/errors/format_test.go:339",
+					".+/github.com/pkg/errors(@v[^/]+)?/format_test.go:339",
 			},
 		}, {
 			func(err error) error { return Wrapf(err, "wrapf-error%d", 1) },
 			[]string{
 				"wrapf-error1",
 				"github.com/pkg/errors.(func·004|TestFormatGeneric.func4)\n\t" +
-					".+/github.com/pkg/errors/format_test.go:346",
+					".+/github.com/pkg/errors(@v[^/]+)?/format_test.go:346",
 			},
 		},
 	}
diff --git a/stack_test.go b/stack_test.go
index 85fc4195..8f0a7650 100644
--- a/stack_test.go
+++ b/stack_test.go
@@ -66,7 +66,7 @@ func TestFrameFormat(t *testing.T) {
 		Frame(initpc),
 		"%+s",
 		"github.com/pkg/errors.init\n" +
-			"\t.+/github.com/pkg/errors/stack_test.go",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go",
 	}, {
 		Frame(0),
 		"%s",
@@ -113,7 +113,7 @@ func TestFrameFormat(t *testing.T) {
 		Frame(initpc),
 		"%+v",
 		"github.com/pkg/errors.init\n" +
-			"\t.+/github.com/pkg/errors/stack_test.go:9",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:9",
 	}, {
 		Frame(0),
 		"%v",
@@ -153,24 +153,24 @@ func TestStackTrace(t *testing.T) {
 	}{{
 		New("ooh"), []string{
 			"github.com/pkg/errors.TestStackTrace\n" +
-				"\t.+/github.com/pkg/errors/stack_test.go:154",
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:154",
 		},
 	}, {
 		Wrap(New("ooh"), "ahh"), []string{
 			"github.com/pkg/errors.TestStackTrace\n" +
-				"\t.+/github.com/pkg/errors/stack_test.go:159", // this is the stack of Wrap, not New
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:159", // this is the stack of Wrap, not New
 		},
 	}, {
 		Cause(Wrap(New("ooh"), "ahh")), []string{
 			"github.com/pkg/errors.TestStackTrace\n" +
-				"\t.+/github.com/pkg/errors/stack_test.go:164", // this is the stack of New
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:164", // this is the stack of New
 		},
 	}, {
 		func() error { return New("ooh") }(), []string{
 			`github.com/pkg/errors.(func·009|TestStackTrace.func1)` +
-				"\n\t.+/github.com/pkg/errors/stack_test.go:169", // this is the stack of New
+				"\n\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:169", // this is the stack of New
 			"github.com/pkg/errors.TestStackTrace\n" +
-				"\t.+/github.com/pkg/errors/stack_test.go:169", // this is the stack of New's caller
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:169", // this is the stack of New's caller
 		},
 	}, {
 		Cause(func() error {
@@ -179,11 +179,11 @@ func TestStackTrace(t *testing.T) {
 			}()
 		}()), []string{
 			`github.com/pkg/errors.(func·010|TestStackTrace.func2.1)` +
-				"\n\t.+/github.com/pkg/errors/stack_test.go:178", // this is the stack of Errorf
+				"\n\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:178", // this is the stack of Errorf
 			`github.com/pkg/errors.(func·011|TestStackTrace.func2)` +
-				"\n\t.+/github.com/pkg/errors/stack_test.go:179", // this is the stack of Errorf's caller
+				"\n\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:179", // this is the stack of Errorf's caller
 			"github.com/pkg/errors.TestStackTrace\n" +
-				"\t.+/github.com/pkg/errors/stack_test.go:180", // this is the stack of Errorf's caller's caller
+				"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:180", // this is the stack of Errorf's caller's caller
 		},
 	}}
 	for i, tt := range tests {
@@ -259,9 +259,9 @@ func TestStackTraceFormat(t *testing.T) {
 		"%+v",
 		"\n" +
 			"github.com/pkg/errors.stackTrace\n" +
-			"\t.+/github.com/pkg/errors/stack_test.go:207\n" +
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:207\n" +
 			"github.com/pkg/errors.TestStackTraceFormat\n" +
-			"\t.+/github.com/pkg/errors/stack_test.go:258",
+			"\t.+/github.com/pkg/errors(@v[^/]+)?/stack_test.go:258",
 	}, {
 		stackTrace()[:2],
 		"%#v",