fix some unit tests

src/components/swap/SwapHeader.tsx

@@ -27,12 +27,12 @@ interface SwapHeaderProps {
   trade?: V2Trade | V3Trade | undefined
 }
 
-export default function SwapHeader({}: SwapHeaderProps) {
+export default function SwapHeader({ trade }: SwapHeaderProps) {
   return (
     <StyledSwapHeader>
       <RowBetween>
         <TYPE.black fontWeight={500} fontSize={16} style={{ opacity: '0.6' }}>
-          Swap
+          Swap {trade instanceof V2Trade ? '(V2)' : trade instanceof V3Trade ? '(V3)' : ''}
         </TYPE.black>
         <RowFixed>
           {/* Send icon appears here when expert mode is toggled on */}

src/pages/Swap/index.tsx

@@ -305,6 +305,8 @@ export default function Swap({ history }: RouteComponentProps) {
 
   const [showDetails, setShowDetails] = useState<boolean>(true)
 
+  const priceImpactTooHigh = priceImpactSeverity > 3 && !isExpertMode
+
   return (
     <>
       <TokenWarningModal
@@ -468,17 +470,11 @@ export default function Swap({ history }: RouteComponentProps) {
                       }}
                       width="100%"
                       id="swap-button"
-                      disabled={
-                        !isValid ||
-                        approvalState !== ApprovalState.APPROVED ||
-                        (priceImpactSeverity > 3 && !isExpertMode)
-                      }
+                      disabled={!isValid || approvalState !== ApprovalState.APPROVED || priceImpactTooHigh}
                       error={isValid && priceImpactSeverity > 2}
                     >
                       <Text fontSize={16} fontWeight={500}>
-                        {priceImpactSeverity > 3 && !isExpertMode
-                          ? `Price Impact High`
-                          : `Swap${priceImpactSeverity > 2 ? ' Anyway' : ''}`}
+                        {priceImpactTooHigh ? `Price Impact High` : `Swap${priceImpactSeverity > 2 ? ' Anyway' : ''}`}
                       </Text>
                     </ButtonError>
                   </AutoColumn>
@@ -500,13 +496,13 @@ export default function Swap({ history }: RouteComponentProps) {
                     }
                   }}
                   id="swap-button"
-                  disabled={!isValid || (priceImpactSeverity > 3 && !isExpertMode) || !!swapCallbackError}
+                  disabled={!isValid || priceImpactTooHigh || !!swapCallbackError}
                   error={isValid && priceImpactSeverity > 2 && !swapCallbackError}
                 >
                   <Text fontSize={20} fontWeight={500}>
                     {swapInputError
                       ? swapInputError
-                      : priceImpactSeverity > 3 && !isExpertMode
+                      : priceImpactTooHigh
                       ? `Price Impact Too High`
                       : `Swap${priceImpactSeverity > 2 ? ' Anyway' : ''}`}
                   </Text>

src/utils/prices.test.ts

-import { ChainId, Token, TokenAmount, TradeType } from '@uniswap/sdk-core'
+import { ChainId, Percent, Token, TokenAmount, TradeType } from '@uniswap/sdk-core'
 import { JSBI, Trade, Pair, Route } from '@uniswap/v2-sdk'
-import { computeTradePriceBreakdown } from './prices'
+import { computeTradePriceBreakdown, warningSeverity } from './prices'
 
 describe('prices', () => {
   const token1 = new Token(ChainId.MAINNET, '0x0000000000000000000000000000000000000001', 18)
@@ -10,7 +10,7 @@ describe('prices', () => {
   const pair12 = new Pair(new TokenAmount(token1, JSBI.BigInt(10000)), new TokenAmount(token2, JSBI.BigInt(20000)))
   const pair23 = new Pair(new TokenAmount(token2, JSBI.BigInt(20000)), new TokenAmount(token3, JSBI.BigInt(30000)))
 
-  describe('computeTradePriceBreakdown', () => {
+  describe('#computeTradePriceBreakdown', () => {
     it('returns undefined for undefined', () => {
       expect(computeTradePriceBreakdown(undefined)).toEqual({
         priceImpactWithoutFee: undefined,
@@ -38,4 +38,22 @@ describe('prices', () => {
       ).toEqual(new TokenAmount(token1, JSBI.BigInt(5)))
     })
   })
+
+  describe('#warningSeverity', () => {
+    it('max for undefined', () => {
+      expect(warningSeverity(undefined)).toEqual(4)
+    })
+    it('correct for 0', () => {
+      expect(warningSeverity(new Percent(0))).toEqual(0)
+    })
+    it('correct for 0.5', () => {
+      expect(warningSeverity(new Percent(5, 1000))).toEqual(0)
+    })
+    it('correct for 5', () => {
+      expect(warningSeverity(new Percent(5, 100))).toEqual(2)
+    })
+    it('correct for 50', () => {
+      expect(warningSeverity(new Percent(5, 10))).toEqual(4)
+    })
+  })
 })

src/utils/prices.ts

@@ -45,7 +45,7 @@ export function computeTradePriceBreakdown(
         : CurrencyAmount.ether(realizedLPFee.multiply(trade.inputAmount.raw).quotient))
 
     return { priceImpactWithoutFee: priceImpactWithoutFeePercent, realizedLPFee: realizedLPFeeAmount }
-  } else {
+  } else if (trade instanceof V3Trade) {
     const realizedLPFee = !trade
       ? undefined
       : ONE_HUNDRED_PERCENT.subtract(
@@ -67,6 +67,11 @@ export function computeTradePriceBreakdown(
       priceImpactWithoutFee: new Percent(0),
       realizedLPFee: realizedLPFeeAmount,
     }
+  } else {
+    return {
+      priceImpactWithoutFee: undefined,
+      realizedLPFee: undefined,
+    }
   }
 }
 
@@ -93,7 +98,7 @@ export function warningSeverity(priceImpact: Percent | undefined): 0 | 1 | 2 | 3
   if (!priceImpact) return 4
   let impact = IMPACT_TIERS.length
   for (const impactLevel of IMPACT_TIERS) {
-    if (priceImpact.lessThan(impactLevel)) return impact as 0 | 1 | 2 | 3 | 4
+    if (impactLevel.lessThan(priceImpact)) return impact as 0 | 1 | 2 | 3 | 4
     impact--
   }
   return 0