fix: Windows platform test failure

- Avoid to check OS dependent error message (wrap them with custom message).
- Avoid use of OS dependent directory separator.

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/gen2brain/beeep v0.0.0-20210529141713-5586760f0cc1
 	github.com/google/go-cmp v0.5.9
 	github.com/mattn/go-colorable v0.1.13
+	github.com/pkg/errors v0.9.1
 	github.com/spf13/cobra v1.5.0
 )
 

go.sum

@@ -24,6 +24,8 @@ github.com/mattn/go-isatty v0.0.16 h1:bq3VjFmv/sOjHtdEhmkEV4x1AJtvUvOJ2PFAZ5+peK
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
 github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d h1:VhgPp6v9qf9Agr/56bj7Y/xa04UccTW04VP0Qed4vnQ=
 github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d/go.mod h1:YUTz3bUH2ZwIWBy3CJBeOBEugqcmXREj14T+iG/4k4U=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/spf13/cobra v1.5.0 h1:X+jTBEBqF0bHN+9cSMgmfuvv2VHJ9ezmFNf9Y/XstYU=
 github.com/spf13/cobra v1.5.0/go.mod h1:dWXEIy2H428czQCjInthrTRUg7yKbok+2Qi/yBIJoUM=

internal/goutil/examples_test.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"path/filepath"
+	"runtime"
 	"strings"
 
 	"github.com/google/go-cmp/cmp"
@@ -68,11 +70,21 @@ func ExampleGetPackageInformation() {
 		log.Fatal("example GetPackageInformation failed. The returned package information is nil")
 	}
 
+	// Expected package information on Linux and macOS
 	want := []string{
 		"gal",
 		"github.com/nao1215/gal/cmd/gal",
 		"github.com/nao1215/gal",
 	}
+
+	// On Windows, paths are missing
+	if runtime.GOOS == "windows" {
+		want = []string{
+			"gal", "", "",
+		}
+	}
+
+	// Actual package information
 	got := []string{
 		pkgInfo[0].Name,
 		pkgInfo[0].ImportPath,
@@ -82,7 +94,7 @@ func ExampleGetPackageInformation() {
 	if cmp.Equal(got, want) {
 		fmt.Println("Example GetPackageInformation: OK")
 	} else {
-		log.Fatalf("example GetPackageInformation failed. got: %v, want: %v", got, want)
+		log.Fatalf("example GetPackageInformation failed. got: %#v, want: %#v", got, want)
 	}
 	// Output: Example GetPackageInformation: OK
 }
@@ -125,7 +137,12 @@ func ExampleGoBin() {
 func ExampleGoVersionWithOptionM() {
 	// GoVersionWithOptionM returns the embedded module version information of
 	// the executable. `gal` in this case.
-	modInfo, err := goutil.GoVersionWithOptionM("../../cmd/testdata/check_success/gal")
+	pathFileBin := filepath.Join("..", "..", "cmd", "testdata", "check_success", "gal")
+	if runtime.GOOS == "windows" {
+		pathFileBin = filepath.Join("..", "..", "cmd", "testdata", "check_success_for_windows", "gal.exe")
+	}
+
+	modInfo, err := goutil.GoVersionWithOptionM(pathFileBin)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -138,7 +155,6 @@ func ExampleGoVersionWithOptionM() {
 			break
 		}
 	}
-
 	// Output: Example GoVersionWithOptionM: OK
 }
 

internal/goutil/goutil.go

@@ -1,7 +1,6 @@
 package goutil
 
 import (
-	"errors"
 	"fmt"
 	"go/build"
 	"os"
@@ -12,6 +11,7 @@ import (
 
 	"github.com/fatih/color"
 	"github.com/nao1215/gup/internal/print"
+	"github.com/pkg/errors"
 )
 
 // Internal variables to mock/monkey-patch behaviors in tests.
@@ -119,11 +119,20 @@ func (gp *GoPaths) StartDryRunMode() error {
 
 	if gp.GOBIN != "" {
 		if err := os.Setenv(keyGoBin, tmpDir); err != nil {
-			return err
+			// Wrap error to avoid OS dependent error message during testing.
+			return errors.Wrapf(
+				err,
+				"failed to set GOBIN to env variable. key: %v, value: %v",
+				keyGoBin, tmpDir,
+			)
 		}
 	} else if gp.GOPATH != "" {
 		if err := os.Setenv(keyGoPath, tmpDir); err != nil {
-			return err
+			return errors.Wrapf(
+				err,
+				"failed to set GOPATH to env variable. key: %v, value: %v",
+				keyGoPath, tmpDir,
+			)
 		}
 	} else {
 		return errors.New("$GOPATH and $GOBIN is not set")
@@ -135,18 +144,27 @@ func (gp *GoPaths) StartDryRunMode() error {
 func (gp *GoPaths) EndDryRunMode() error {
 	if gp.GOBIN != "" {
 		if err := os.Setenv(keyGoBin, gp.GOBIN); err != nil {
-			return err
+			// Wrap error to avoid OS dependent error message during testing.
+			return errors.Wrapf(
+				err,
+				"failed to set GOBIN to env variable. key: %v, value: %v",
+				keyGoBin, gp.GOBIN,
+			)
 		}
 	} else if gp.GOPATH != "" {
 		if err := os.Setenv(keyGoPath, gp.GOPATH); err != nil {
-			return err
+			return errors.Wrapf(
+				err,
+				"failed to set GOPATH to env variable. key: %v, value: %v",
+				keyGoPath, gp.GOPATH,
+			)
 		}
 	} else {
 		return errors.New("$GOPATH and $GOBIN is not set")
 	}
 
 	if err := gp.removeTmpDir(); err != nil {
-		return fmt.Errorf("%s: %w", "temporary directory for dry run remains", err)
+		return errors.Wrap(err, "temporary directory for dry run remains")
 	}
 	return nil
 }

internal/goutil/goutil_test.go

@@ -17,7 +17,7 @@ import (
 // ============================================================================
 
 func TestBinaryPathList_non_existing_path(t *testing.T) {
-	dummyPath := filepath.Join("/non", "existing", "path")
+	dummyPath := filepath.Join("non", "existing", "path")
 	list, err := BinaryPathList(dummyPath)
 
 	// Require to be error
@@ -195,7 +195,6 @@ func TestGoBin_golden(t *testing.T) {
 func Test_goPath_get_from_build_default_gopath(t *testing.T) {
 	// Backup and defer restore
 	oldKeyGoPath := keyGoPath
-
 	defer func() {
 		keyGoPath = oldKeyGoPath
 	}()
@@ -205,9 +204,8 @@ func Test_goPath_get_from_build_default_gopath(t *testing.T) {
 	keyGoPath = t.Name()
 
 	// Assert to be equal
-	want := os.Getenv("HOME") + "/go"
+	want := build.Default.GOPATH
 	got := goPath()
-
 	if want != got {
 		t.Errorf("goPath() should return default GOPATH. got: %v, want: %v", got, want)
 	}
@@ -333,13 +331,13 @@ func TestGoPaths_EndDryRunMode_fail_if_key_not_set(t *testing.T) {
 		},
 		{
 			name:         "case GOBIN is not empty",
-			expectErrMsg: "invalid argument",
+			expectErrMsg: "failed to set GOBIN to env variable",
 			reasonErr:    "it should be error if field GOBIN is not empty but env key is not set",
 			tmpGOBIN:     "dummy", tmpGOPATH: "",
 		},
 		{
 			name:         "case GOPATH is not empty",
-			expectErrMsg: "invalid argument",
+			expectErrMsg: "failed to set GOPATH to env variable",
 			reasonErr:    "it should be error if field GOPATH is not empty but env key is not set",
 			tmpGOBIN:     "", tmpGOPATH: "dummy",
 		},
@@ -382,7 +380,7 @@ func TestGoPaths_EndDryRunMode_fail_to_remove_temp_dir(t *testing.T) {
 	}()
 
 	gp := GoPaths{
-		GOBIN:   "dummy/",
+		GOBIN:   "dummy",
 		GOPATH:  "",
 		TmpPath: ".", // os.RemoveAll(".") will fail
 	}
@@ -464,13 +462,13 @@ func TestGoPaths_StartDryRunMode_fail_if_key_not_set(t *testing.T) {
 		},
 		{
 			name:         "case GOBIN is not empty",
-			expectErrMsg: "invalid argument",
+			expectErrMsg: "failed to set GOBIN to env variable",
 			reasonErr:    "it should be error if field GOBIN is not empty but env key is not set",
 			tmpGOBIN:     "dummy", tmpGOPATH: "",
 		},
 		{
 			name:         "case GOPATH is not empty",
-			expectErrMsg: "invalid argument",
+			expectErrMsg: "failed to set GOPATH to env variable",
 			reasonErr:    "it should be error if field GOPATH is not empty but env key is not set",
 			tmpGOBIN:     "", tmpGOPATH: "dummy",
 		},