test: add scale-band assertions for sFLR, flrETH, and FtsoV2 LTS feeds

src/lib/lts/LibFtsoV2LTS.sol

@@ -7,6 +7,7 @@ import {IFtsoRegistry, LibFlareContractRegistry} from "../registry/LibFlareContr
 import {FtsoV2Interface} from "../../vendor/flare-smart-contracts-v2/userInterfaces/LTS/FtsoV2Interface.sol";
 import {StalePrice} from "../../err/ErrFtso.sol";
 import {IFeeCalculator} from "../../vendor/flare-smart-contracts-v2/userInterfaces/IFeeCalculator.sol";
+import {LibDecimalFloat, Float} from "rain-math-float-0.1.1/src/lib/LibDecimalFloat.sol";
 
 /// @dev FTSO feed IDs.
 /// https://dev.flare.network/ftso/feeds
@@ -83,9 +84,11 @@ library LibFtsoV2LTS {
     /// the feed timestamp plus timeout.
     /// @param feedId The bytes21 Flare V2 feed ID to read.
     /// @param timeout Max age in seconds before the price is considered stale.
-    /// @return value The feed value in wei (1e18 fixed-point).
+    /// @return The feed value as a Float, tagged at this boundary with the
+    /// 18-decimal (wei) scale of `getFeedByIdInWei`, so callers cannot
+    /// reinterpret the scale.
     //forge-lint: disable-next-line(mixed-case-function)
-    function ftsoV2LTSGetFeed(bytes21 feedId, uint256 timeout) internal returns (uint256) {
+    function ftsoV2LTSGetFeed(bytes21 feedId, uint256 timeout) internal returns (Float) {
         // Fetch the FTSO from the registry.
         FtsoV2Interface ftsoRegistry = LibFlareContractRegistry.getFtsoV2LTS();
         IFeeCalculator feeCalculator = LibFlareContractRegistry.getFeeCalculator();
@@ -107,6 +110,6 @@ library LibFtsoV2LTS {
             revert StalePrice(timestamp, timeout);
         }
 
-        return value;
+        return LibDecimalFloat.fromFixedDecimalLosslessPacked(value, 18);
     }
 }

test/lib/lts/FeedConsumer.sol

@@ -3,9 +3,10 @@
 pragma solidity =0.8.25;
 
 import {LibFtsoV2LTS} from "src/lib/lts/LibFtsoV2LTS.sol";
+import {Float} from "rain-math-float-0.1.1/src/lib/LibDecimalFloat.sol";
 
 contract FeedConsumer {
-    function getFeedValue(bytes21 feedId, uint256 timeout) external payable returns (uint256) {
+    function getFeedValue(bytes21 feedId, uint256 timeout) external payable returns (Float) {
         return LibFtsoV2LTS.ftsoV2LTSGetFeed(feedId, timeout);
     }
 }

test/src/lib/flreth/LibDineroFlrEth.t.sol

@@ -25,6 +25,16 @@ contract LibDineroFlrEthTest is Test {
         assertEq(rate18, 0.989103076939285809e18);
     }
 
+    function testFlrEthRateScaleBand() external view {
+        uint256 ethPerFlrEth = LibDineroFlrEth.getETHPerFLRETH18();
+        assertGe(ethPerFlrEth, 0.1e18, "ETH/flrETH rate below 0.1 -- scale may have changed");
+        assertLe(ethPerFlrEth, 10e18, "ETH/flrETH rate above 10 -- scale may have changed");
+
+        uint256 flrEthPerEth = LibDineroFlrEth.getFLRETHPerETH18();
+        assertGe(flrEthPerEth, 0.1e18, "flrETH/ETH rate below 0.1 -- scale may have changed");
+        assertLe(flrEthPerEth, 10e18, "flrETH/ETH rate above 10 -- scale may have changed");
+    }
+
     // External wrappers needed so vm.expectRevert captures the outer call frame
     // (not the inner LSTPerToken/tokensPerLST staticcall which returns, not reverts).
     function _callGetETHPerFLRETH18() external {

test/src/lib/lts/LibFtsoV2LTS.t.sol

@@ -12,13 +12,23 @@ import {IGoverned, IGovernanceSettings} from "src/interface/IGoverned.sol";
 import {IGovernedFeeCalculator} from "src/interface/IGovernedFeeCalculator.sol";
 import {StalePrice} from "src/err/ErrFtso.sol";
 import {FeedConsumer} from "test/lib/lts/FeedConsumer.sol";
+import {LibDecimalFloat, Float} from "rain-math-float-0.1.1/src/lib/LibDecimalFloat.sol";
 
 contract LibFtsoV2LTSTest is Test {
     function testFtsoV2LTSGetFeed() external {
         vm.createSelectFork(LibFork.rpcUrlFlare(vm), BLOCK_NUMBER);
 
-        uint256 feedValue = LibFtsoV2LTS.ftsoV2LTSGetFeed(ETH_USD_FEED_ID, 3600);
-        assertEq(feedValue, 2522.575e18);
+        Float feedValue = LibFtsoV2LTS.ftsoV2LTSGetFeed(ETH_USD_FEED_ID, 3600);
+        assertEq(LibDecimalFloat.toFixedDecimalLossless(feedValue, 18), 2522.575e18);
+    }
+
+    function testLtsFeedScaleBand() external {
+        vm.createSelectFork(LibFork.rpcUrlFlare(vm), BLOCK_NUMBER);
+
+        Float feedValue = LibFtsoV2LTS.ftsoV2LTSGetFeed(ETH_USD_FEED_ID, 3600);
+        uint256 feedValueWei = LibDecimalFloat.toFixedDecimalLossless(feedValue, 18);
+        assertGe(feedValueWei, 1e18, "ETH/USD LTS feed below 1 -- scale may have changed");
+        assertLe(feedValueWei, 1e24, "ETH/USD LTS feed above 1e6 -- scale may have changed");
     }
 
     function testFtsoV2LTSGetFeedStale() external {
@@ -37,7 +47,7 @@ contract LibFtsoV2LTSTest is Test {
 
         FeedConsumer feedConsumer = new FeedConsumer();
         vm.warp(1729795768 + 3600);
-        uint256 value = feedConsumer.getFeedValue(ETH_USD_FEED_ID, 3600);
+        uint256 value = LibDecimalFloat.toFixedDecimalLossless(feedConsumer.getFeedValue(ETH_USD_FEED_ID, 3600), 18);
         assertGt(value, 0);
     }
 
@@ -68,7 +78,7 @@ contract LibFtsoV2LTSTest is Test {
 
         FeedConsumer feedConsumer = new FeedConsumer();
         vm.warp(1729795768);
-        uint256 value = feedConsumer.getFeedValue(ETH_USD_FEED_ID, 0);
+        uint256 value = LibDecimalFloat.toFixedDecimalLossless(feedConsumer.getFeedValue(ETH_USD_FEED_ID, 0), 18);
         assertGt(value, 0);
     }
 
@@ -116,15 +126,15 @@ contract LibFtsoV2LTSTest is Test {
 
         vm.deal(alice, fee);
         assertEq(alice.balance, fee);
-        uint256 feedValue = feedConsumer.getFeedValue{value: alice.balance}(ETH_USD_FEED_ID, 3600);
-        assertEq(feedValue, 2522.575e18);
+        Float feedValue = feedConsumer.getFeedValue{value: alice.balance}(ETH_USD_FEED_ID, 3600);
+        assertEq(LibDecimalFloat.toFixedDecimalLossless(feedValue, 18), 2522.575e18);
         assertEq(alice.balance, 0);
 
         // #56 — overpayment: surplus is stranded in the consumer (documents current behavior;
         // replace with refund assertion when a refund mechanism is added).
         vm.deal(alice, uint256(fee) + 1 ether);
-        uint256 overpaidValue = feedConsumer.getFeedValue{value: alice.balance}(ETH_USD_FEED_ID, 3600);
-        assertEq(overpaidValue, 2522.575e18);
+        Float overpaidValue = feedConsumer.getFeedValue{value: alice.balance}(ETH_USD_FEED_ID, 3600);
+        assertEq(LibDecimalFloat.toFixedDecimalLossless(overpaidValue, 18), 2522.575e18);
         assertEq(address(feedConsumer).balance, 1 ether);
         assertEq(alice.balance, 0);
     }

test/src/lib/sflr/LibSceptreStakedFlare.t.sol

@@ -24,6 +24,12 @@ contract LibSceptreStakedFlareTest is Test {
         assertEq(rate18, 0.877817288626455057e18);
     }
 
+    function testSflrRateScaleBand() external view {
+        uint256 rate18 = LibSceptreStakedFlare.getSFLRPerFLR18();
+        assertGe(rate18, 0.1e18, "sFLR/FLR rate below 0.1 -- scale may have changed");
+        assertLe(rate18, 10e18, "sFLR/FLR rate above 10 -- scale may have changed");
+    }
+
     function testGetSFLRPerFLR18ZeroReverts() external {
         vm.mockCall(
             address(SFLR_CONTRACT),