Tests (and bug fixes!) for the format-bytes helper

ui/app/helpers/format-bytes.js

@@ -14,12 +14,12 @@ const UNITS = ['Bytes', 'KiB', 'MiB'];
  */
 export function formatBytes([bytes]) {
   let unitIndex = 0;
-  while (bytes >= 1024 && unitIndex < UNITS.length) {
+  while (bytes >= 1024 && unitIndex < UNITS.length - 1) {
     bytes /= 1024;
     unitIndex++;
   }
 
-  return `${Math.ceil(bytes)} ${UNITS[unitIndex]}`;
+  return `${Math.floor(bytes)} ${UNITS[unitIndex]}`;
 }
 
 export default Helper.helper(formatBytes);

ui/tests/unit/helpers/format-bytes-test.js

@@ -0,0 +1,28 @@
+import { module, test } from 'ember-qunit';
+import { formatBytes } from 'nomad-ui/helpers/format-bytes';
+
+module('format-bytes', 'Unit | Helper | format-bytes');
+
+test('formats x < 1024 as bytes', function(assert) {
+  assert.equal(formatBytes([0]), '0 Bytes');
+  assert.equal(formatBytes([100]), '100 Bytes');
+  assert.equal(formatBytes([1023]), '1023 Bytes');
+});
+
+test('formats 1024 <= x < 1024 * 1024 as KiB', function(assert) {
+  assert.equal(formatBytes([1024]), '1 KiB');
+  assert.equal(formatBytes([125952]), '123 KiB');
+  assert.equal(formatBytes([1024 * 1024 - 1]), '1023 KiB');
+});
+
+test('formats 1024 * 1024 <= x < 1024 * 1024 * 1024 as MiB', function(assert) {
+  assert.equal(formatBytes([1024 * 1024]), '1 MiB');
+  assert.equal(formatBytes([128974848]), '123 MiB');
+});
+
+test('formats x > 1024 * 1024 * 1024 as MiB, since it is the highest allowed unit', function(
+  assert
+) {
+  assert.equal(formatBytes([1024 * 1024 * 1024]), '1024 MiB');
+  assert.equal(formatBytes([1024 * 1024 * 1024 * 4]), '4096 MiB');
+});