From e5a1f2539fe5408788129974176b25fb8c21cdae Mon Sep 17 00:00:00 2001
From: Mark Tyers <aa7401@coventry.ac.uk>
Date: Fri, 30 Nov 2018 09:35:43 +0000
Subject: [PATCH] added simple spies example

---
 .../05_advanced_testing/03_spies_basic/app.js |  9 +++++++++
 .../03_spies_basic/app.test.js                | 19 ++++++++++++++++++
 .../03_spies_basic/math.js                    |  7 +++++++
 .../03_spies_basic/package.json               | 20 +++++++++++++++++++
 4 files changed, 55 insertions(+)
 create mode 100644 exercises/05_advanced_testing/03_spies_basic/app.js
 create mode 100644 exercises/05_advanced_testing/03_spies_basic/app.test.js
 create mode 100644 exercises/05_advanced_testing/03_spies_basic/math.js
 create mode 100644 exercises/05_advanced_testing/03_spies_basic/package.json

diff --git a/exercises/05_advanced_testing/03_spies_basic/app.js b/exercises/05_advanced_testing/03_spies_basic/app.js
new file mode 100644
index 0000000..a410b87
--- /dev/null
+++ b/exercises/05_advanced_testing/03_spies_basic/app.js
@@ -0,0 +1,9 @@
+
+'use strict'
+
+const math = require('./math.js')
+
+module.exports.doAdd = (a, b) => math.add(a, b)
+module.exports.doSubtract = (a, b) => math.subtract(a, b)
+module.exports.doMultiply = (a, b) => math.multiply(a, b)
+module.exports.doDivide = (a, b) => math.divide(a, b)
diff --git a/exercises/05_advanced_testing/03_spies_basic/app.test.js b/exercises/05_advanced_testing/03_spies_basic/app.test.js
new file mode 100644
index 0000000..e78f2f3
--- /dev/null
+++ b/exercises/05_advanced_testing/03_spies_basic/app.test.js
@@ -0,0 +1,19 @@
+
+'use strict'
+
+const app = require('./app')
+const math = require('./math')
+
+test('calls math.add', () => {
+	const addMock = jest.spyOn(math, 'add')
+
+	// override the implementation
+	addMock.mockImplementation(() => 'mock')
+	expect(app.doAdd(1, 2)).toEqual('mock')
+	expect(addMock).toHaveBeenCalledWith(1, 2)
+
+	// restore the original implementation
+	addMock.mockRestore()
+	expect(app.doAdd(1, 2)).toEqual(3)
+	console.log(addMock.mock.calls)
+})
diff --git a/exercises/05_advanced_testing/03_spies_basic/math.js b/exercises/05_advanced_testing/03_spies_basic/math.js
new file mode 100644
index 0000000..57dde10
--- /dev/null
+++ b/exercises/05_advanced_testing/03_spies_basic/math.js
@@ -0,0 +1,7 @@
+
+'use strict'
+
+module.exports.add = (a, b) => a + b
+module.exports.subtract = (a, b) => b - a
+module.exports.multiply = (a, b) => a * b
+module.exports.divide = (a, b) => b / a
diff --git a/exercises/05_advanced_testing/03_spies_basic/package.json b/exercises/05_advanced_testing/03_spies_basic/package.json
new file mode 100644
index 0000000..7c9a5e4
--- /dev/null
+++ b/exercises/05_advanced_testing/03_spies_basic/package.json
@@ -0,0 +1,20 @@
+{
+  "name": "03_spies",
+  "version": "1.0.0",
+  "description": "",
+  "main": "app.js",
+  "scripts": {
+    "test": "./node_modules/.bin/jest",
+    "watch": "./node_modules/.bin/jest --noStackTrace --watchAll"
+  },
+  "author": "",
+  "license": "ISC",
+  "jest": {
+    "testEnvironment": "node",
+    "verbose": true,
+    "collectCoverage": true
+  },
+  "devDependencies": {
+    "jest": "^23.6.0"
+  }
+}