Stabilize colors

test/helper/colors.js

@@ -0,0 +1,40 @@
+/**
+ * This module is maintained to promote separation between the tests and the
+ * implementation.
+ */
+'use strict';
+
+const ansiStyles = require('ansi-styles');
+
+function make(name) {
+	const style = ansiStyles[name];
+	return function (string) {
+		return style.open + string + style.close;
+	};
+}
+const bold = make('bold');
+const white = make('white');
+const gray = make('gray');
+
+// The following color definitions are contextual so that they produce expected
+// values which mimic the behavior of the Chalk library.
+const isSimpleWindowsTerm = process.platform === 'win32' && !(process.env.TERM || '').toLowerCase().startsWith('xterm');
+const openDim = isSimpleWindowsTerm ? '' : ansiStyles.dim.open;
+const openBlue = isSimpleWindowsTerm ? '\u001B[94m' : ansiStyles.blue.open;
+// "Use `bold` by default on Windows"
+// https://github.com/chalk/chalk/issues/36
+const blue = string => openBlue + string + ansiStyles.blue.close;
+// "(Windows) chalk.gray.dim not visible"
+// https://github.com/chalk/chalk/issues/58
+const dimGray = string => gray(openDim + string + ansiStyles.dim.close);
+
+module.exports = {
+	blue,
+	boldWhite: string => bold(white(string)),
+	dimGray,
+	gray,
+	green: make('green'),
+	magenta: make('magenta'),
+	red: make('red'),
+	yellow: make('yellow')
+};