tools: introduce tools.Indent() to indent strings

tools/str_tools.go

@@ -100,3 +100,15 @@ func Longest(strs []string) string {
 
 	return longest
 }
+
+// Indent returns a string which prepends "\t" TAB characters to the beginning
+// of each line in the given string "str".
+func Indent(str string) string {
+	indented := strings.Replace(str, "\n", "\n\t", -1)
+	if len(indented) > 0 {
+		indented = "\t" + indented
+	}
+
+	return indented
+}
+

tools/str_tools_test.go

@@ -112,3 +112,21 @@ func TestLjustLeftJustifiesString(t *testing.T) {
 
 	assert.Equal(t, expected, Ljust(unjust))
 }
+
+func TestIndentIndentsStrings(t *testing.T) {
+	assert.Equal(t, "\tfoo\n\tbar", Indent("foo\nbar"))
+}
+
+func TestIndentIndentsSingleLineStrings(t *testing.T) {
+	assert.Equal(t, "\tfoo", Indent("foo"))
+}
+
+func TestIndentReturnsEmptyStrings(t *testing.T) {
+	assert.Equal(t, "", Indent(""))
+}
+
+func TestUndentRemovesLeadingWhitespace(t *testing.T) {
+	assert.Equal(t, "foo", Undent("\t\t\tfoo"))
+	assert.Equal(t, "foo", Undent("foo"))
+	assert.Equal(t, "foo", Undent("    foo"))
+}

tools/text.go

@@ -0,0 +1 @@
+package tools

tools/text_test.go

@@ -0,0 +1 @@
+package tools_test