Use more powerful package name determination algorithm

#76

pegomock/main.go

@@ -21,7 +21,7 @@ import (
 	"strings"
 	"time"
 
-	"gopkg.in/alecthomas/kingpin.v2"
+	kingpin "gopkg.in/alecthomas/kingpin.v2"
 
 	"github.com/petergtz/pegomock/pegomock/filehandling"
 	"github.com/petergtz/pegomock/pegomock/remove"
@@ -93,7 +93,8 @@ func Run(cliArgs []string, out io.Writer, in io.Reader, app *kingpin.Application
 
 		realPackageOut := *packageOut
 		if *packageOut == "" {
-			realPackageOut = filepath.Base(workingDir) + "_test"
+			realPackageOut, err = DeterminePackageNameIn(workingDir)
+			app.FatalIfError(err, "Could not determine package name.")
 		}
 
 		realDestination := *destination

pegomock/main_test.go

@@ -21,11 +21,12 @@ import (
 	"path/filepath"
 	"strings"
 
-	"gopkg.in/alecthomas/kingpin.v2"
+	kingpin "gopkg.in/alecthomas/kingpin.v2"
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	main "github.com/petergtz/pegomock/pegomock"
+
 	. "github.com/petergtz/pegomock/pegomock/testutil"
 
 	"testing"

pegomock/package_name.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/tools/go/loader"
+)
+
+func DeterminePackageNameIn(dir string) (string, error) {
+	fileInfos, e := ioutil.ReadDir(dir)
+	if e != nil {
+		return "", fmt.Errorf("Could not get files in directory %v: %v", dir, e.Error())
+	}
+	var filenames []string
+	var testFilenames []string
+	for _, fileInfo := range fileInfos {
+		if fileInfo.IsDir() || !strings.HasSuffix(fileInfo.Name(), ".go") {
+			continue
+		}
+		if strings.HasSuffix(fileInfo.Name(), "_test.go") {
+			testFilenames = append(testFilenames, fileInfo.Name())
+		} else {
+			filenames = append(filenames, fileInfo.Name())
+		}
+	}
+	packageName, e := packageNameFrom(dir, testFilenames)
+	if e != nil {
+		return "", e
+	}
+	if packageName != "" {
+		return packageName, nil
+	}
+	packageName, e = packageNameFrom(dir, filenames)
+	if e != nil {
+		return "", e
+	}
+	if packageName != "" {
+		return packageName + "_test", nil
+	}
+	packageName = strings.Replace(filepath.Base(dir), "-", "_", -1)
+	if packageName != "" {
+		return packageName + "_test", nil
+	}
+	panic("Unexpected error when determining the package name of the mock file.")
+}
+
+func packageNameFrom(dir string, filenames []string) (string, error) {
+	conf := loader.Config{
+		Cwd:         dir,
+		AllowErrors: true,
+	}
+	conf.CreateFromFilenames("", filenames...)
+	program, e := conf.Load()
+	if e != nil {
+		panic(e)
+	}
+	if len(program.Created[0].Errors) != 0 {
+		return "", fmt.Errorf("Error while determining Go package name from Go file in %v: %v", dir, program.Created[0].Errors)
+	}
+	return program.Created[0].Pkg.Name(), nil
+}

pegomock/package_name_test.go

@@ -0,0 +1,73 @@
+package main_test
+
+import (
+	"go/build"
+	"os"
+
+	. "github.com/petergtz/pegomock/pegomock/testutil"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	main "github.com/petergtz/pegomock/pegomock"
+)
+
+var _ = Describe("DetermineBla", func() {
+	var (
+		packageDir string
+	)
+	BeforeEach(func() {
+		packageDir = joinPath(build.Default.GOPATH, "src", "package_dir")
+	})
+
+	JustBeforeEach(func() {
+		Expect(os.MkdirAll(packageDir, 0755)).To(Succeed())
+	})
+
+	AfterEach(func() {
+		Expect(os.RemoveAll(packageDir)).To(Succeed())
+	})
+
+	Context("only one go file", func() {
+		It("names the package name after package name + _test suffix", func() {
+			WriteFile(joinPath(packageDir, "mydisplay.go"), "package package_name")
+
+			Expect(main.DeterminePackageNameIn(packageDir)).To(Equal("package_name_test"))
+		})
+	})
+
+	Context("multiple go files with different package names", func() {
+		It("fails", func() {
+			WriteFile(joinPath(packageDir, "mydisplay.go"), "package package_name")
+			WriteFile(joinPath(packageDir, "other.go"), "package other_package_name")
+
+			_, e := main.DeterminePackageNameIn(packageDir)
+			Expect(e).To(MatchError(ContainSubstring("Error while determining Go package")))
+		})
+	})
+
+	Context("go file and go test file", func() {
+		It("determines the package name from the test file", func() {
+			WriteFile(joinPath(packageDir, "mydisplay.go"), "package package_name")
+			WriteFile(joinPath(packageDir, "mydisplay_test.go"), "package non_conventional_package_name_test")
+
+			Expect(main.DeterminePackageNameIn(packageDir)).To(Equal("non_conventional_package_name_test"))
+		})
+	})
+
+	Context("no files", func() {
+		It("names the package after the directory name base", func() {
+			Expect(main.DeterminePackageNameIn(packageDir)).To(Equal("package_dir_test"))
+		})
+
+		Context("current dir with dashes in name", func() {
+			BeforeEach(func() {
+				packageDir = joinPath(build.Default.GOPATH, "src", "package-dir-with-dashes")
+			})
+
+			It("names the package after the directory name base, but replace dashes with underscores", func() {
+				Expect(main.DeterminePackageNameIn(packageDir)).To(Equal("package_dir_with_dashes_test"))
+			})
+		})
+	})
+
+})