diff --git a/CHANGELOG.md b/CHANGELOG.md
index a0816b3e96..2dfa5b2c9e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Add test check URLs of vendors.
 - Add test of match current week number on clock module with showWeek configuration.
 - Add test default modules present modules/default/defaultmodules.js.
+- Add unit test calendar_modules function capFirst.
 
 ### Updated
 - Added missing keys to Polish translation.
diff --git a/tests/unit/functions/calendar_spec.js b/tests/unit/functions/calendar_spec.js
new file mode 100644
index 0000000000..2c7f62f881
--- /dev/null
+++ b/tests/unit/functions/calendar_spec.js
@@ -0,0 +1,36 @@
+var fs = require("fs");
+var path = require("path");
+var chai = require("chai");
+var expect = chai.expect;
+var vm = require("vm");
+
+
+describe("Functions into modules/default/calendar/calendar.js", function() {
+
+	// Fake for use by calendar.js
+	Module = {}
+	Module.definitions = {};
+	Module.register = function (name, moduleDefinition) {
+		Module.definitions[name] = moduleDefinition;
+	};
+
+	// load calendar.js
+	require("../../../modules/default/calendar/calendar.js");
+
+	describe("capFirst", function() {
+		words = {
+			"rodrigo": "Rodrigo",
+			"123m": "123m",
+			"magic mirror": "Magic mirror",
+			",a": ",a",
+			"ñandú": "Ñandú"
+		};
+
+		Object.keys(words).forEach(word => {
+			it(`for ${word} should return ${words[word]}`, function() {
+				expect(Module.definitions.calendar.capFirst(word)).to.equal(words[word]);
+			});
+		});
+	});
+});
+