Fix error handling from USDC rate limiting call. (#1036)

Fix bug where USDC rate limiter was checking the wrong error response.

core/services/ocr2/plugins/ccip/tokendata/usdc/usdc.go

@@ -164,7 +164,7 @@ func NewUSDCTokenDataReaderWithHttpClient(
 // attestation response. When called back to back, or multiple times
 // concurrently, responses are delayed according how the request interval is
 // configured.
-func (s *TokenDataReader) ReadTokenData(ctx context.Context, msg cciptypes.EVM2EVMOnRampCCIPSendRequestedWithMeta, tokenIndex int) (messageAndAttestation []byte, err error) {
+func (s *TokenDataReader) ReadTokenData(ctx context.Context, msg cciptypes.EVM2EVMOnRampCCIPSendRequestedWithMeta, tokenIndex int) ([]byte, error) {
 	if tokenIndex < 0 || tokenIndex >= len(msg.TokenAmounts) {
 		return nil, fmt.Errorf("token index out of bounds")
 	}
@@ -177,7 +177,7 @@ func (s *TokenDataReader) ReadTokenData(ctx context.Context, msg cciptypes.EVM2E
 	if s.rate != nil {
 		// Wait blocks until it the attestation API can be called or the
 		// context is Done.
-		if waitErr := s.rate.Wait(ctx); err != nil {
+		if waitErr := s.rate.Wait(ctx); waitErr != nil {
 			return nil, fmt.Errorf("usdc rate limiting error: %w", waitErr)
 		}
 	}
@@ -197,7 +197,7 @@ func (s *TokenDataReader) ReadTokenData(ctx context.Context, msg cciptypes.EVM2E
 	switch attestationResp.Status {
 	case attestationStatusSuccess:
 		// The USDC pool needs a combination of the message body and the attestation
-		messageAndAttestation, err = encodeMessageAndAttestation(messageBody, attestationResp.Attestation)
+		messageAndAttestation, err := encodeMessageAndAttestation(messageBody, attestationResp.Attestation)
 		if err != nil {
 			return nil, fmt.Errorf("failed to encode messageAndAttestation : %w", err)
 		}

core/services/ocr2/plugins/ccip/tokendata/usdc/usdc_test.go

@@ -335,15 +335,15 @@ func TestUSDCReader_rateLimiting(t *testing.T) {
 			rateConfig:   100 * time.Millisecond,
 			testDuration: 1 * time.Millisecond,
 			timeout:      1 * time.Millisecond,
-			err:          "usdc rate limiting error: rate: Wait(n=1) would exceed context deadline",
+			err:          "usdc rate limiting error:",
 		},
 		{
 			name:         "timeout after second request",
 			requests:     5,
 			rateConfig:   100 * time.Millisecond,
 			testDuration: 100 * time.Millisecond,
 			timeout:      150 * time.Millisecond,
-			err:          "usdc rate limiting error: rate: Wait(n=1) would exceed context deadline",
+			err:          "usdc rate limiting error:",
 		},
 	}
 
@@ -405,14 +405,15 @@ func TestUSDCReader_rateLimiting(t *testing.T) {
 			// Collect errors
 			errorFound := false
 			for err := range errorChan {
-				if tc.err != "" && !strings.Contains(err.Error(), tc.err) {
+				if tc.err != "" && strings.Contains(err.Error(), tc.err) {
 					errorFound = true
 				} else if err != nil && !strings.Contains(err.Error(), "get usdc token 0 end offset") {
 					// Ignore that one error, it's expected because of how mocking is used.
 					// Anything else is unexpected.
 					require.Fail(t, "unexpected error", err)
 				}
 			}
+
 			if tc.err != "" {
 				assert.True(t, errorFound)
 			}