👯 Improve uint128x2 and add tests

Author: KimlikDAO-bot

contracts/uint128x2.sol

@@ -4,15 +4,15 @@ pragma solidity ^0.8.20;
 
 type uint128x2 is uint256;
 
-function uint128x2From(uint256 hi, uint256 lo) pure returns (uint128x2) {
-    return uint128x2.wrap(hi << 128 | lo);
+function uint128x2From(uint256 high, uint256 low) pure returns (uint128x2) {
+    return uint128x2.wrap(high << 128 | low);
 }
 
-function hi128(uint128x2 n) pure returns (uint256) {
+function hi(uint128x2 n) pure returns (uint256) {
     return uint128x2.unwrap(n) >> 128;
 }
 
-function lo128(uint128x2 n) pure returns (uint256) {
+function lo(uint128x2 n) pure returns (uint256) {
     return uint128(uint128x2.unwrap(n));
 }
 
@@ -24,14 +24,18 @@ function decLo(uint128x2 self, uint256 delta) pure returns (uint128x2) {
 
 function inc(uint128x2 self, uint256 delta) pure returns (uint128x2) {
     unchecked {
-        return uint128x2.wrap(uint128x2.unwrap(self) + (delta | delta << 128));
+        return uint128x2.wrap(uint128x2.unwrap(self) + (delta | (delta << 128)));
     }
 }
 
 function dec(uint128x2 self, uint256 delta) pure returns (uint128x2) {
     unchecked {
-        return uint128x2.wrap(uint128x2.unwrap(self) - (delta | delta << 128));
+        return uint128x2.wrap(uint128x2.unwrap(self) - (delta | (delta << 128)));
     }
 }
 
-using {hi128, lo128, decLo, inc, dec} for uint128x2 global;
+function equal(uint128x2 self, uint128x2 other) pure returns (bool) {
+    return uint128x2.unwrap(self) == uint128x2.unwrap(other);
+}
+
+using {hi, lo, decLo, inc, dec, equal as ==} for uint128x2 global;

test/uint128x2.t.sol

@@ -2,14 +2,33 @@
 
 pragma solidity ^0.8.0;
 
-import {Test} from "forge-std/Test.sol";
 import {uint128x2, uint128x2From} from "contracts/uint128x2.sol";
+import {Test} from "forge-std/Test.sol";
 
-contract integersTest is Test {
+contract uint128x2Test is Test {
     function testAccessors() public pure {
         uint128x2 pair = uint128x2From(1, 2);
 
-        assertEq(pair.lo128(), 2);
-        assertEq(pair.hi128(), 1);
+        assertEq(pair.lo(), 2);
+        assertEq(pair.hi(), 1);
+    }
+
+    function testIncDec() public pure {
+        uint128x2 pair = uint128x2From(300, 500);
+        pair = pair.inc(200);
+
+        assertEq(pair.hi(), 500);
+        assertEq(pair.lo(), 700);
+
+        pair = pair.dec(200);
+
+        assertEq(pair.hi(), 300);
+        assertEq(pair.lo(), 500);
+
+        uint128x2 pair2 = uint128x2From(type(uint128).max, 10);
+        uint128x2 pair3 = pair2.dec(10);
+        pair3 = pair3.inc(10);
+
+        assert(pair2 == pair3);
     }
 }