Ui/pricing metrics params (#10083)

metrics route takes start and end params and passes to the date display field, as well as the route's API call

ui/tests/unit/helpers/parse-date-string-test.js

@@ -0,0 +1,47 @@
+import { parseDateString } from 'vault/helpers/parse-date-string';
+import { module, test } from 'qunit';
+import { compareAsc } from 'date-fns';
+
+module('Unit | Helpers | parse-date-string', function() {
+  test('it returns the first of the month when date like MM-YYYY passed in', function(assert) {
+    let expected = new Date(2020, 3, 1);
+    let result = parseDateString('04-2020');
+    assert.equal(compareAsc(expected, result), 0);
+  });
+
+  test('it can handle a date format like MM/YYYY', function(assert) {
+    let expected = new Date(2020, 11, 1);
+    let result = parseDateString('12/2020', '/');
+    assert.equal(compareAsc(expected, result), 0);
+  });
+
+  test('it throws an error with passed separator if bad format', function(assert) {
+    let result;
+    try {
+      result = parseDateString('01-12-2020');
+    } catch (e) {
+      result = e.message;
+    }
+    assert.equal('Please use format MM-YYYY', result);
+  });
+
+  test('it throws an error with wrong separator', function(assert) {
+    let result;
+    try {
+      result = parseDateString('12/2020', '.');
+    } catch (e) {
+      result = e.message;
+    }
+    assert.equal('Please use format MM.YYYY', result);
+  });
+
+  test('it throws an error if month is invalid', function(assert) {
+    let result;
+    try {
+      result = parseDateString('13-2020');
+    } catch (e) {
+      result = e.message;
+    }
+    assert.equal('Not a valid month value', result);
+  });
+});