[DOC beta] Assert that both modelName and id are passed to peekRecord

Adds expectAssertion test for the new assertion, as well as an
expectAssertion test for the existing assertion that a model name
(string) must be passed instead of a model class.

addon/-private/system/store.js

@@ -1039,6 +1039,7 @@ Store = Service.extend({
   peekRecord(modelName, id) {
     heimdall.increment(peekRecord);
     assert(`You need to pass a model name to the store's peekRecord method`, isPresent(modelName));
+    assert(`You need to pass both a model name and id to the store's peekRecord method`, isPresent(modelName) && isPresent(id));
     assert(`Passing classes to store methods has been removed. Please pass a dasherized string instead of ${modelName}`, typeof modelName === 'string');
     let normalizedModelName = normalizeModelName(modelName);
 

tests/unit/store/peek-record-test.js

@@ -1,5 +1,6 @@
 import setupStore from 'dummy/tests/helpers/store';
 import Ember from 'ember';
+import testInDebug from 'dummy/tests/helpers/test-in-debug';
 
 import {module, test} from 'qunit';
 
@@ -41,3 +42,20 @@ test('peekRecord should return null if the record is not in the store ', functio
     assert.equal(null, store.peekRecord('person', 1), 'peekRecord returns null if the corresponding record is not in the store');
   });
 });
+
+testInDebug('peekRecord should assert if not passed both model name and id', function(assert) {
+  run(() => {
+    assert.expectAssertion(() => {
+      store.peekRecord('my-id');
+    }, /You need to pass both a model name and id/);
+  });
+});
+
+testInDebug('peekRecord should assert if passed a model class instead of model name', function(assert) {
+  run(() => {
+    assert.expectAssertion(() => {
+      let modelClass = Ember.Object.extend();
+      store.peekRecord(modelClass, 'id');
+    }, /Passing classes to store methods has been removed/);
+  });
+});