refactor: Combine loops in PrestoSerializerTest.validateLexer (facebo…

…okincubator#11434)

Summary:
Combine multiple tests in separate loops to just one to improve readability.

Pull Request resolved: facebookincubator#11434

Reviewed By: kevinwilfong

Differential Revision: D65880657

Pulled By: Yuhta

fbshipit-source-id: 6c2c813e240206f894a2537eabd6ee3510233739

velox/serializers/tests/PrestoSerializerTest.cpp

@@ -180,17 +180,20 @@ class PrestoSerializerTest
     const auto status = serializer::presto::PrestoVectorSerde::lex(
         input, tokens, &paramOptions);
     EXPECT_TRUE(status.ok()) << status.message();
+
     size_t tokenLengthSum = 0;
-    for (auto const& token : tokens) {
-      tokenLengthSum += token.length;
-    }
-    for (auto const& token : tokens) {
+    for (size_t i = 0; i < tokens.size(); ++i) {
+      const auto& token = tokens[i];
+
       // The lexer should not produce empty tokens
       EXPECT_NE(token.length, 0);
-    }
-    for (size_t i = 1; i < tokens.size(); ++i) {
-      // The lexer should merge consecutive tokens of the same type
-      EXPECT_NE(tokens[i].tokenType, tokens[i - 1].tokenType);
+      // Compute tokenLengthSum to validate with input.size().
+      tokenLengthSum += token.length;
+
+      if (i > 0) {
+        // The lexer should merge consecutive tokens of the same type
+        EXPECT_NE(token.tokenType, tokens[i - 1].tokenType);
+      }
     }
     EXPECT_EQ(tokenLengthSum, input.size());
   }