Add option to re-use schema cache between requests (#2979)

* Add option to reuse database controller between requests. Clear schema cache when deleting everything

* Add test

* Rename setting to persistSchemaCache to more accurately reflect effect

* Repurpose option to determine whether to randomize cache prefix. Restore Config.js controller creation. Add tests

* Fix bug with missing parameter passed to to SchemaCache

* Renaming and formatting

* Fix property name typo

* Rename option to avoid double negative and still be falsey by default. Style fix

spec/EnableSingleSchemaCache.spec.js

@@ -0,0 +1,49 @@
+const auth = require('../src/Auth');
+const Config = require('../src/Config');
+const rest = require('../src/rest');
+
+describe('Enable single schema cache', () => {
+  beforeEach((done) => {
+    reconfigureServer({
+      enableSingleSchemaCache: true,
+      schemaCacheTTL: 30000
+    }).then(() => {
+      done();
+    });
+  });
+
+  it('can perform multiple create and query operations', (done) => {
+    let config = fakeRequestForConfig();
+    let nobody = auth.nobody(config);
+    rest.create(config, nobody, 'Foo', {type: 1}).then(() => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      return rest.create(config, nobody, 'Foo', {type: 2});
+    }).then(() => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      return rest.create(config, nobody, 'Bar');
+    }).then(() => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      return rest.find(config, nobody, 'Bar', {type: 1});
+    }).then((response) => {
+      fail('Should throw error');
+      done();
+    }, (error) => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      expect(error).toBeDefined();
+      return rest.find(config, nobody, 'Foo', {type: 1});
+    }).then((response) => {
+      config = fakeRequestForConfig();
+      nobody = auth.nobody(config);
+      expect(response.results.length).toEqual(1);
+      done();
+    });
+  });
+});
+
+const fakeRequestForConfig = function() {
+  return new Config('test');
+};