Unit testing (#32)

* add testing lib

* remove coverage folder from git

* finished basic test setup

* fix tests typescript and import paths

* add first snapshot

* testing utils

* rename test files; update script flags; ++tests

* testing utils functions

* testing downloadAndResize wip

* remove download test

* specify unwanted coverage paths;
remove update snapshots flag

* fix strings tests

* testing downloadAndResize method

* increasing testing

* fixing snapshots wip

* fixed shell mobile snapshot

* adding snapshots for the screens

* fix onboard snapshot

* fix typescript issues

* fix TabsSelector snapshot

* Account for testing device's locale in ago() tests

* Remove platform detection on regex

Co-authored-by: Paul Frazee <pfrazee@gmail.com>

__tests__/lib/errors.test.ts

@@ -0,0 +1,19 @@
+import {isNetworkError} from '../../src/lib/errors'
+
+describe('isNetworkError', () => {
+  const inputs = [
+    'TypeError: Network request failed',
+    'Uncaught TypeError: Cannot read property x of undefined',
+    'Uncaught RangeError',
+    'Error: Aborted',
+  ]
+  const outputs = [true, false, false, true]
+
+  it('correctly distinguishes network errors', () => {
+    for (let i = 0; i < inputs.length; i++) {
+      const input = inputs[i]
+      const result = isNetworkError(input)
+      expect(result).toEqual(outputs[i])
+    }
+  })
+})