add tests for subtract, sum and title

package.json

@@ -1,6 +1,6 @@
 {
   "name": "timelion",
-  "version": "5.0.0-0.1.306",
+  "version": "5.0.0-0.1.307",
   "dependencies": {
     "body-parser": "^1.12.0",
     "boom": "^2.8.0",

series_functions/__test__/subtract.js

@@ -0,0 +1,21 @@
+const filename = require('path').basename(__filename);
+const fn = require(`../${filename}`);
+
+const _ = require('lodash');
+const expect = require('chai').expect;
+const invoke = require('./helpers/invoke_series_fn.js');
+
+describe(filename, () => {
+
+  let seriesList;
+  beforeEach(() => {
+    seriesList = require('./fixtures/seriesList.js')();
+  });
+
+  it('it subtracts a number', () => {
+    return invoke(fn, [seriesList, 2]).then((r) => {
+      expect(_.map(r.output.list[1].data, 1)).to.eql([98, 48, 48, 18]);
+    });
+  });
+
+});

series_functions/__test__/sum.js

@@ -0,0 +1,21 @@
+const filename = require('path').basename(__filename);
+const fn = require(`../${filename}`);
+
+const _ = require('lodash');
+const expect = require('chai').expect;
+const invoke = require('./helpers/invoke_series_fn.js');
+
+describe(filename, () => {
+
+  let seriesList;
+  beforeEach(() => {
+    seriesList = require('./fixtures/seriesList.js')();
+  });
+
+  it('it adds a number', () => {
+    return invoke(fn, [seriesList, 2]).then((r) => {
+      expect(_.map(r.output.list[1].data, 1)).to.eql([102, 52, 52, 22]);
+    });
+  });
+
+});

series_functions/__test__/title.js

@@ -0,0 +1,21 @@
+const filename = require('path').basename(__filename);
+const fn = require(`../${filename}`);
+
+const _ = require('lodash');
+const expect = require('chai').expect;
+const invoke = require('./helpers/invoke_series_fn.js');
+
+describe(filename, () => {
+
+  let seriesList;
+  beforeEach(() => {
+    seriesList = require('./fixtures/seriesList.js')();
+  });
+
+  it('sets the title property', () => {
+    return invoke(fn, [seriesList, 'beer']).then((r) => {
+      _.each(r.output.list, (series) => expect(series._title).to.equal('beer'));
+    });
+  });
+
+});