feat(display): add methods to display

- Add `indent`, `faint`, and `underline` methods to `display`
- Add tests for the above

internal/display/faint.go

@@ -0,0 +1,8 @@
+package display
+
+import "fmt"
+
+// Faint returns an faint string
+func Faint(str string) string {
+	return fmt.Sprintf(fmt.Sprintf("\033[2m%s\033[0m", str))
+}

internal/display/faint_test.go

@@ -0,0 +1,14 @@
+package display
+
+import (
+	"testing"
+)
+
+// TestFaint asserts that Faint applies faint formatting
+func TestFaint(t *testing.T) {
+	want := "\033[2mfoo\033[0m"
+	got := Faint("foo")
+	if want != got {
+		t.Errorf("failed to faint: want: %s, got: %s", want, got)
+	}
+}

internal/display/indent.go

@@ -0,0 +1,16 @@
+package display
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Indent prepends each line of a string with a tab
+func Indent(str string) string {
+	out := ""
+	for _, line := range strings.Split(str, "\n") {
+		out += fmt.Sprintf("\t%s\n", line)
+	}
+
+	return strings.TrimSuffix(out, "\n")
+}

internal/display/indent_test.go

@@ -0,0 +1,12 @@
+package display
+
+import "testing"
+
+// TestIndent asserts that Indent prepends a tab to each line
+func TestIndent(t *testing.T) {
+	got := Indent("foo\nbar\nbaz")
+	want := "\tfoo\n\tbar\n\tbaz"
+	if got != want {
+		t.Errorf("failed to indent: want: %s, got: %s", want, got)
+	}
+}

internal/display/underline.go

@@ -0,0 +1,8 @@
+package display
+
+import "fmt"
+
+// Underline returns an underlined string
+func Underline(str string) string {
+	return fmt.Sprintf(fmt.Sprintf("\033[4m%s\033[0m", str))
+}

internal/display/underline_test.go

@@ -0,0 +1,14 @@
+package display
+
+import (
+	"testing"
+)
+
+// TestUnderline asserts that Underline applies underline formatting
+func TestUnderline(t *testing.T) {
+	want := "\033[4mfoo\033[0m"
+	got := Underline("foo")
+	if want != got {
+		t.Errorf("failed to underline: want: %s, got: %s", want, got)
+	}
+}