basic test environment works

src/IERC20Metadata.sol

@@ -1,22 +0,0 @@
-// SPDX-License-Identifier: UNLICENSED
-pragma solidity =0.7.6;
-
-import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
-
-// the version of OpenZeppelin required by Uniswap v3 doesn't have IERC20Metadata yet, so we copy it here.
-interface IERC20Metadata is IERC20 {
-    /**
-     * @dev Returns the name of the token.
-     */
-    function name() external view returns (string memory);
-
-    /**
-     * @dev Returns the symbol of the token.
-     */
-    function symbol() external view returns (string memory);
-
-    /**
-     * @dev Returns the decimals places of the token.
-     */
-    function decimals() external view returns (uint8);
-}

src/MockERC20.sol

@@ -1,10 +1,10 @@
-import "openzeppelin/contracts/token/ERC20/ERC20.sol";
-import "./IERC20Metadata.sol";
+pragma solidity =0.7.6;
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 
 
-contract MockERC20 is ERC20, IERC20Metadata {
+contract MockERC20 is ERC20 {
 
-    constructor(string name, string symbol, uint8 decimals)
+    constructor(string memory name, string memory symbol, uint8 decimals)
     ERC20(name, symbol)
     {
         _setupDecimals(decimals);

src/Util.sol

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity =0.7.6;
+pragma abicoder v2;
+
+library Util {
+    function roundTick(int24 tick, int24 window) public pure returns (int24) {
+        // NOTE: we round half toward zero
+        int24 mod = tick % window;
+        if (tick < 0)
+            return - mod <= window / 2 ? tick - mod : tick - (window + mod);
+        else
+            return mod > window / 2 ? tick + (window - mod) : tick - mod;
+    }
+}