testutil/pkgdata: Add TarEntry shorthand constructors

internal/testutil/pkgdata.go

@@ -277,3 +277,41 @@ func MustMakeDeb(entries []TarEntry) []byte {
 	}
 	return data
 }
+
+// Reg is a shortcut for creating a regular file TarEntry structure (with
+// tar.Typeflag set tar.TypeReg). Reg stands for "REGular file".
+func Reg(mode int64, path, content string) TarEntry {
+	return TarEntry{
+		Header: tar.Header{
+			Typeflag: tar.TypeReg,
+			Name:     path,
+			Mode:     mode,
+		},
+		Content: []byte(content),
+	}
+}
+
+// Dir is a shortcut for creating a directory TarEntry structure (with
+// tar.Typeflag set to tar.TypeDir). Dir stands for "DIRectory".
+func Dir(mode int64, path string) TarEntry {
+	return TarEntry{
+		Header: tar.Header{
+			Typeflag: tar.TypeDir,
+			Name:     path,
+			Mode:     mode,
+		},
+	}
+}
+
+// Lnk is a shortcut for creating a symbolic link TarEntry structure (with
+// tar.Typeflag set to tar.TypeSymlink). Lnk stands for "symbolic LiNK".
+func Lnk(mode int64, path, target string) TarEntry {
+	return TarEntry{
+		Header: tar.Header{
+			Typeflag: tar.TypeSymlink,
+			Name:     path,
+			Mode:     mode,
+			Linkname: target,
+		},
+	}
+}

internal/testutil/pkgdata_test.go

@@ -398,3 +398,42 @@ func (s *S) TestMustMakeDeb(c *C) {
 		},
 	}})
 }
+
+func (s *S) TestTarEntryShortHands(c *C) {
+	var testCases = []struct {
+		shorthand testutil.TarEntry
+		result    testutil.TarEntry
+	}{{
+		testutil.Reg(0600, "./document.txt", "cats are best"),
+		testutil.TarEntry{
+			Header: tar.Header{
+				Typeflag: tar.TypeReg,
+				Name:     "./document.txt",
+				Mode:     0600,
+			},
+			Content: []byte("cats are best"),
+		},
+	}, {
+		testutil.Dir(0755, "./home/user"),
+		testutil.TarEntry{
+			Header: tar.Header{
+				Typeflag: tar.TypeDir,
+				Name:     "./home/user",
+				Mode:     0755,
+			},
+		},
+	}, {
+		testutil.Lnk(0755, "./lib", "./usr/lib/"),
+		testutil.TarEntry{
+			Header: tar.Header{
+				Typeflag: tar.TypeSymlink,
+				Name:     "./lib",
+				Mode:     0755,
+				Linkname: "./usr/lib/",
+			},
+		},
+	}}
+	for _, test := range testCases {
+		c.Assert(test.shorthand, DeepEquals, test.result)
+	}
+}