diff --git a/test/index.js b/test/index.js
index 4405b738..a396a58d 100644
--- a/test/index.js
+++ b/test/index.js
@@ -6,14 +6,33 @@ const oauth2Module = require('./../index.js');
 const { createModuleConfig } = require('./_module-config');
 
 test('@create => throws a validation error when no configuration is provided', (t) => {
-  const createModule = () => oauth2Module.create();
-
-  t.throws(createModule);
+  t.throws(() => oauth2Module.create());
 });
 
-test('@create => creates a new instance', (t) => {
+test('@create => creates a new instance with the minimal required configuration', (t) => {
   const config = createModuleConfig();
-  const createModule = () => oauth2Module.create(config);
 
-  t.notThrows(createModule);
+  t.notThrows(() => oauth2Module.create(config));
+});
+
+test('@create => creates a new instance with empty credentials', (t) => {
+  const config = createModuleConfig({
+    client: {
+      id: '',
+      secret: '',
+    },
+  });
+
+  t.notThrows(() => oauth2Module.create(config));
+});
+
+test('@create => creates a new instance with visual non-control characters', (t) => {
+  const config = createModuleConfig({
+    client: {
+      id: '\x20hello\x7E',
+      secret: '\x20world\x7E',
+    },
+  });
+
+  t.notThrows(() => oauth2Module.create(config));
 });