Added IsDir and more tests

fs.go

@@ -4,10 +4,19 @@ import "os"
 
 // Exists returns if a file exists
 func Exists(path string) bool {
-	if _, err := os.Stat(path); err != nil {
-		return false
-	} else if os.IsNotExist(err) {
+	if _, err := os.Stat(path); os.IsNotExist(err) {
 		return false
 	}
 	return true
 }
+
+func IsDir(path string) bool {
+	info, err := os.Stat(path)
+	if err != nil {
+		return false
+	}
+	if info.IsDir() {
+		return true
+	}
+	return false
+}

fs_test.go

@@ -9,8 +9,11 @@ import (
 
 func TestExists(t *testing.T) {
 	tmp, err := ioutil.TempDir("", "fs-test-")
+	defer func() {
+		os.RemoveAll(tmp)
+	}()
 	if err != nil {
-		panic(err)
+		t.Fatalf("couldn't create temp dir: %v", err)
 	}
 
 	filename := filepath.Join(tmp, "foo")
@@ -28,4 +31,49 @@ func TestExists(t *testing.T) {
 	if !Exists(filename) {
 		t.Errorf("failure to find existant file: %s", filename)
 	}
+
+	dirname := filepath.Join(tmp, "somedir")
+	if err := os.Mkdir(dirname, 0777); err != nil {
+		t.Errorf("problem creating directory: %v", err)
+	}
+
+	if !Exists(dirname) {
+		t.Errorf("failure to find existant directory: %s", dirname)
+	}
+}
+
+func TestIsDir(t *testing.T) {
+	tmp, err := ioutil.TempDir("", "fs-test-")
+	defer func() {
+		os.RemoveAll(tmp)
+	}()
+	if err != nil {
+		t.Fatalf("couldn't create temp dir: %v", err)
+	}
+	dirname := filepath.Join(tmp, "somedir")
+	if err := os.Mkdir(dirname, 0777); err != nil {
+		t.Errorf("problem creating directory: %v", err)
+	}
+
+	if isdir := IsDir(filepath.Join(tmp, "notexist")); isdir {
+		t.Errorf("failed to correctly interpret non-existant file: got %t, want %t", isdir, false)
+	}
+
+	if !Exists(dirname) {
+		t.Errorf("failure to find existant directory: %s", dirname)
+	}
+
+	if !IsDir(dirname) {
+		t.Errorf("failure to detect directory: %s", dirname)
+	}
+
+	filename := filepath.Join(tmp, "foo")
+	f, err := os.Create(filename)
+	if err != nil {
+		t.Errorf("problem opening fresh file (%q): %v", filename, err)
+	}
+	f.Close()
+	if isdir := IsDir(filename); isdir {
+		t.Errorf("failure to correctly interpret file as directory; got %t, want %t", isdir, false)
+	}
 }