tests(erc20): add erc20 query tests (evmos#2023)

CHANGELOG.md

@@ -81,6 +81,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 - (utils) [#2010](https://github.com/evmos/evmos/pull/2010) Add utils function to create ibc denom trace.
 - (erc20) [#2012](https://github.com/evmos/evmos/pull/2012) Adjust ERC20 extension approvals to handle multiple denominations.
 - (osmosis-outpost) [#2017](https://github.com/evmos/evmos/pull/2017) Refactor types, errors and precompile struct.
+- (erc20) [#2023](https://github.com/evmos/evmos/pull/2023) Add tests for ERC20 precompile queries.
 - (osmosis-outpost) [#2025](https://github.com/evmos/evmos/pull/2025) Use a struct to wrap parsed parameters from Solidity.
 
 ### Bug Fixes

precompiles/erc20/query.go

@@ -16,7 +16,7 @@ import (
 	authzkeeper "github.com/cosmos/cosmos-sdk/x/authz/keeper"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 	transfertypes "github.com/cosmos/ibc-go/v7/modules/apps/transfer/types"
-	"github.com/evmos/evmos/v15/precompiles/authorization"
+	auth "github.com/evmos/evmos/v15/precompiles/authorization"
 	transferkeeper "github.com/evmos/evmos/v15/x/ibc/transfer/keeper"
 
 	"github.com/ethereum/go-ethereum/accounts/abi"
@@ -43,7 +43,7 @@ const (
 )
 
 // Name returns the name of the token. If the token metadata is registered in the
-// bank module, it returns its name. Otherwise it returns the base denomination of
+// bank module, it returns its name. Otherwise, it returns the base denomination of
 // the token capitalized (eg. uatom -> Atom).
 func (p Precompile) Name(
 	ctx sdk.Context,
@@ -57,20 +57,12 @@ func (p Precompile) Name(
 		return method.Outputs.Pack(metadata.Name)
 	}
 
-	// Infer the denomination name from the coin denomination base denom
-	denomTrace, err := GetDenomTrace(p.transferKeeper, ctx, p.tokenPair.Denom)
+	baseDenom, err := p.getBaseDenomFromIBCVoucher(ctx, p.tokenPair.Denom)
 	if err != nil {
-		// FIXME: return 'not supported' (same error as when you call the method on an ERC20.sol)
 		return nil, err
 	}
 
-	// safety check
-	if len(denomTrace.BaseDenom) < 3 {
-		// FIXME: return not supported (same error as when you call the method on an ERC20.sol)
-		return nil, nil
-	}
-
-	name := strings.ToUpper(string(denomTrace.BaseDenom[1])) + denomTrace.BaseDenom[2:]
+	name := strings.ToUpper(string(baseDenom[1])) + baseDenom[2:]
 	return method.Outputs.Pack(name)
 }
 
@@ -89,19 +81,12 @@ func (p Precompile) Symbol(
 		return method.Outputs.Pack(metadata.Symbol)
 	}
 
-	denomTrace, err := GetDenomTrace(p.transferKeeper, ctx, p.tokenPair.Denom)
+	baseDenom, err := p.getBaseDenomFromIBCVoucher(ctx, p.tokenPair.Denom)
 	if err != nil {
-		// FIXME: return not supported (same error as when you call the method on an ERC20.sol)
 		return nil, err
 	}
 
-	// safety check
-	if len(denomTrace.BaseDenom) < 3 {
-		// FIXME: return not supported (same error as when you call the method on an ERC20.sol)
-		return nil, nil
-	}
-
-	symbol := strings.ToUpper(denomTrace.BaseDenom[1:])
+	symbol := strings.ToUpper(baseDenom[1:])
 	return method.Outputs.Pack(symbol)
 }
 
@@ -131,22 +116,34 @@ func (p Precompile) Decimals(
 			return method.Outputs.Pack(uint8(18))
 		}
 		// FIXME: return not supported (same error as when you call the method on an ERC20.sol)
-		return nil, nil
+		return nil, fmt.Errorf(
+			"invalid base denomination; should be either micro ('u[...]') or atto ('a[...]'); got: %q",
+			denomTrace.BaseDenom,
+		)
 	}
 
-	var decimals uint32
-	for i := len(metadata.DenomUnits); i >= 0; i-- {
+	var (
+		decimals     uint32
+		displayFound bool
+	)
+	for i := len(metadata.DenomUnits) - 1; i >= 0; i-- {
 		if metadata.DenomUnits[i].Denom == metadata.Display {
 			decimals = metadata.DenomUnits[i].Exponent
+			displayFound = true
 			break
 		}
 	}
 
+	if !displayFound {
+		// FIXME: return not supported (same error as when you call the method on an ERC20.sol)
+		return nil, fmt.Errorf("display denomination not found for denom: %q", p.tokenPair.Denom)
+	}
+
 	if decimals > math.MaxUint8 {
-		return nil, errors.New("uint8 overflow: invalid decimals")
+		return nil, fmt.Errorf("uint8 overflow: invalid decimals: %d", decimals)
 	}
 
-	return method.Outputs.Pack(uint8(decimals)) //#nosec G701
+	return method.Outputs.Pack(uint8(decimals)) //#nosec G701 // we are checking for overflow above
 }
 
 // TotalSupply returns the amount of tokens in existence. It fetches the supply
@@ -208,7 +205,7 @@ func (p Precompile) Allowance(
 }
 
 // GetDenomTrace returns the denomination trace from the corresponding IBC denomination. If the
-// denomination is is not an IBC voucher or the trace is not found, it returns an error.
+// denomination is not an IBC voucher or the trace is not found, it returns an error.
 func GetDenomTrace(
 	transferKeeper transferkeeper.Keeper,
 	ctx sdk.Context,
@@ -239,7 +236,7 @@ func GetAuthzExpirationAndAllowance(
 	grantee, granter common.Address,
 	denom string,
 ) (authz.Authorization, *time.Time, *big.Int, error) {
-	authorization, expiration, err := authorization.CheckAuthzExists(ctx, authzKeeper, grantee, granter, SendMsgURL)
+	authorization, expiration, err := auth.CheckAuthzExists(ctx, authzKeeper, grantee, granter, SendMsgURL)
 	// TODO: return error if doesn't exist?
 	if err != nil {
 		return nil, nil, common.Big0, err
@@ -254,3 +251,21 @@ func GetAuthzExpirationAndAllowance(
 	allowance := sendAuth.SpendLimit.AmountOfNoDenomValidation(denom)
 	return authorization, expiration, allowance.BigInt(), nil
 }
+
+// getBaseDenomFromIBCVoucher returns the base denomination from the given IBC voucher denomination.
+func (p Precompile) getBaseDenomFromIBCVoucher(ctx sdk.Context, denom string) (string, error) {
+	// Infer the denomination name from the coin denomination base denom
+	denomTrace, err := GetDenomTrace(p.transferKeeper, ctx, denom)
+	if err != nil {
+		// FIXME: return 'not supported' (same error as when you call the method on an ERC20.sol)
+		return "", err
+	}
+
+	// safety check
+	if len(denomTrace.BaseDenom) < 3 {
+		// FIXME: return not supported (same error as when you call the method on an ERC20.sol)
+		return "", fmt.Errorf("invalid base denomination; should be at least length 3; got: %q", denomTrace.BaseDenom)
+	}
+
+	return denomTrace.BaseDenom, nil
+}