tests: refactor solidity test cases (#249)

* Refactor

* add script to run all tests

* Spawn ethermintd in node script

* Update README

* kill process when test finished

* add new test case

* add yarn.lock inside tests to be tracked

tests/solidity/suites/storage/contracts/EventTest.sol

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-3.0
+
+pragma solidity >=0.7.0 <0.9.0;
+
+/**
+ * @title Storage
+ * @dev Store & retrieve value in a variable
+ */
+contract EventTest {
+
+    uint256 number;
+
+    event ValueStored1(
+        uint value1
+    );
+    event ValueStored2(
+        string msg,
+        uint value1
+    );
+    event ValueStored3(
+        string msg,
+        uint indexed value1,
+        uint value2
+    );
+
+    function store(uint256 num) public {
+        number = num;
+    }
+
+    function storeWithEvent(uint256 num) public {
+        number = num;
+        emit ValueStored1(num);
+        emit ValueStored2("TestMsg", num);
+        emit ValueStored3("TestMsg", num, num);
+    }
+
+}

tests/solidity/suites/storage/contracts/Storage.sol

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-3.0
+
+pragma solidity >=0.7.0 <0.9.0;
+
+/**
+ * @title Storage
+ * @dev Store & retrieve value in a variable
+ */
+contract Storage {
+
+    uint256 number;
+
+    /**
+     * @dev Store value in variable
+     * @param num value to store
+     */
+    function store(uint256 num) public {
+        number = num;
+    }
+
+    /**
+     * @dev Return value 
+     * @return value of 'number'
+     */
+    function retrieve() public view returns (uint256){
+        return number;
+    }
+
+    function shouldRevert() public {
+        require(false, 'This must REVERT');
+    }
+}