added test

Author: aditya520

target_chains/ethereum/contracts/forge-test/utils/PythTestUtils.t.sol

@@ -283,10 +283,33 @@ contract PythTestUtilsTest is
     PythTestUtils,
     IPythEvents
 {
-    using PythUtils for *;
-
     function testConvertToUnit() public {
+        // Price can't be negative
+        vm.expectRevert();
+        PythUtils.convertToUint(-100, -5, 18);
+
+        // Exponent can't be positive
         vm.expectRevert();
-        uint256 price = PythUtils.convertToUnit(-100, -5, 18);
+        PythUtils.convertToUint(100, 5, 18);
+
+        // Price with 18 decimals and exponent -5
+        assertEq(
+            PythUtils.convertToUint(100, -5, 18),
+            1000000000000000 // 100 * 10^13
+        );
+
+        // Price with 9 decimals and exponent -2
+        assertEq(
+            PythUtils.convertToUint(100, -2, 9),
+            1000000000 // 100 * 10^7
+        );
+
+        // Price with 4 decimals and exponent -5
+        assertEq(PythUtils.convertToUint(100, -5, 4), 10);
+
+        // Price with 5 decimals and exponent -2
+        // @note: We will lose precision here as price is
+        // 0.00001 and we are targetDecimals is 2.
+        assertEq(PythUtils.convertToUint(100, -5, 2), 0);
     }
 }

target_chains/ethereum/sdk/solidity/PythUtils.sol

@@ -7,6 +7,8 @@ library PythUtils {
     /// @param expo The Pyth price exponent
     /// @param targetDecimals The target number of decimals
     /// @return The price as a uint256
+    /// @dev Function will loose precision if targetDecimals is less than the Pyth price decimals
+    /// e.g. If the price is 0.000123 and the targetDecimals is 2, the result will be 0
     function convertToUint(
         int64 price,
         int32 expo,