diff --git a/tests/jerry-test-suite/11/11.08/11.08.06/11.08.06-008.js b/tests/jerry-test-suite/11/11.08/11.08.06/11.08.06-008.js
new file mode 100644
index 0000000000..1f41e2a714
--- /dev/null
+++ b/tests/jerry-test-suite/11/11.08/11.08.06/11.08.06-008.js
@@ -0,0 +1,17 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+var a = null;
+var c = a instanceof Object;
+assert (!c);
diff --git a/tests/jerry/arithmetics-2.js b/tests/jerry/arithmetics-2.js
index 396546557a..c4554cccd9 100644
--- a/tests/jerry/arithmetics-2.js
+++ b/tests/jerry/arithmetics-2.js
@@ -51,3 +51,5 @@ try {
 catch (e) {
   assert (e instanceof ReferenceError);
 }
+
+assert (0.1 + 0.2 != 0.3);
diff --git a/tests/jerry/arithmetics-bignums.js b/tests/jerry/arithmetics-bignums.js
index 6b46bb3d60..39ee7a3d2a 100644
--- a/tests/jerry/arithmetics-bignums.js
+++ b/tests/jerry/arithmetics-bignums.js
@@ -26,3 +26,5 @@ assert(big == 2147483649); // overflow on 32bit numbers
 assert ((1152921504606846976).toString() === "1152921504606847000")
 
 assert (1.797693134862315808e+308 === Infinity);
+
+assert (9999999999999999 == 10000000000000000);
diff --git a/tests/jerry/unusual.js b/tests/jerry/unusual.js
new file mode 100644
index 0000000000..85cfd0a291
--- /dev/null
+++ b/tests/jerry/unusual.js
@@ -0,0 +1,27 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+var x = [0];
+assert (x == x);
+assert (x == !x);
+assert (Array(3) == ",,");
+
+assert ([] + [] == "");
+assert ([] + {} == "[object Object]");
+assert (eval ("{} + []") == 0);
+assert (isNaN (eval ("{} + {}")));
+assert ({} + [] == "[object Object]");
+assert ({} + {} == "[object Object][object Object]");
+
+assert ((! + [] + [] + ![]) === "truefalse");