fixes stack trace test

stacktrace.go

@@ -2,8 +2,10 @@ package godog
 
 import (
 	"fmt"
+	"go/build"
 	"io"
 	"path"
+	"path/filepath"
 	"runtime"
 	"strings"
 )
@@ -26,6 +28,13 @@ func (f stackFrame) file() string {
 	return file
 }
 
+func trimGoPath(file string) string {
+	for _, p := range filepath.SplitList(build.Default.GOPATH) {
+		file = strings.Replace(file, filepath.Join(p, "src")+string(filepath.Separator), "", 1)
+	}
+	return file
+}
+
 // line returns the line number of source code of the
 // function for this Frame's pc.
 func (f stackFrame) line() int {
@@ -66,7 +75,7 @@ func (f stackFrame) Format(s fmt.State, verb rune) {
 				io.WriteString(s, "unknown")
 			} else {
 				file, _ := fn.FileLine(pc)
-				fmt.Fprintf(s, "%s\n\t%s", fn.Name(), file)
+				fmt.Fprintf(s, "%s\n\t%s", fn.Name(), trimGoPath(file))
 			}
 		default:
 			io.WriteString(s, path.Base(f.file()))

stacktrace_test.go

@@ -2,6 +2,7 @@ package godog
 
 import (
 	"fmt"
+	"runtime"
 	"strings"
 	"testing"
 )
@@ -14,10 +15,26 @@ func trimLineSpaces(s string) string {
 	return strings.Join(res, "\n")
 }
 
+func callstack1() *stack {
+	return callstack2()
+}
+
+func callstack2() *stack {
+	return callstack3()
+}
+
+func callstack3() *stack {
+	const depth = 4
+	var pcs [depth]uintptr
+	n := runtime.Callers(1, pcs[:])
+	var st stack = pcs[0:n]
+	return &st
+}
+
 func TestStacktrace(t *testing.T) {
 	err := &traceError{
 		msg:   "err msg",
-		stack: callStack(),
+		stack: callstack1(),
 	}
 
 	expect := "err msg"
@@ -27,10 +44,14 @@ func TestStacktrace(t *testing.T) {
 	}
 
 	expect = trimLineSpaces(`err msg
-testing.tRunner
-	/usr/lib/go/src/testing/testing.go:657
-runtime.goexit
-	/usr/lib/go/src/runtime/asm_amd64.s:2197`)
+github.com/DATA-DOG/godog.callstack3
+github.com/DATA-DOG/godog/stacktrace_test.go:29
+github.com/DATA-DOG/godog.callstack2
+github.com/DATA-DOG/godog/stacktrace_test.go:23
+github.com/DATA-DOG/godog.callstack1
+github.com/DATA-DOG/godog/stacktrace_test.go:19
+github.com/DATA-DOG/godog.TestStacktrace
+github.com/DATA-DOG/godog/stacktrace_test.go:37`)
 
 	actual = trimLineSpaces(fmt.Sprintf("%+v", err))
 	if expect != actual {