Validate expense/reimbursement forms

Adds some general helpers and styles for minimalistic form validation.

tests/unit/utils/is-valid-amount-test.js

@@ -0,0 +1,22 @@
+import isValidAmount from 'kredits-web/utils/is-valid-amount';
+import { module, test } from 'qunit';
+
+module('Unit | Utility | is-valid-amount', function() {
+  test('it returns true for valid amounts', function(assert) {
+    assert.ok(isValidAmount('1'));
+    assert.ok(isValidAmount('1.0'));
+    assert.ok(isValidAmount('0.3'));
+    assert.ok(isValidAmount('0.3333923'));
+    assert.ok(isValidAmount(1));
+    assert.ok(isValidAmount(1.0));
+    assert.ok(isValidAmount(0.3));
+    assert.ok(isValidAmount(0.3333923));
+  });
+
+  test('it returns false for invalid amounts', function(assert) {
+    assert.notOk(isValidAmount('0'));
+    assert.notOk(isValidAmount(0));
+    assert.notOk(isValidAmount(''));
+    assert.notOk(isValidAmount('foo'));
+  });
+});