chore: add max-result-size integration test

Author: avallete

Diff for: packages/pg/test/integration/client/max-result-size-tests.js

@@ -0,0 +1,55 @@
+'use strict'
+var helper = require('./test-helper')
+var assert = require('assert')
+
+const pool = new helper.pg.Pool({
+  maxResultSize: 100, // Very small size limit (100 bytes)
+  // Keep other connection parameters from helper
+  ...helper.args
+})
+
+// Flag to track if we've seen the first type of error message
+let sizeExceededErrorSeen = false
+
+pool.connect(
+  assert.success(function (client) {
+    // First create a temp table
+    client.query('CREATE TEMP TABLE large_result_test(id SERIAL, data TEXT)', assert.success(function () {
+      // Insert data that will exceed the size limit when selected
+      const insertPromises = []
+      for (let i = 0; i < 20; i++) {
+        // Each row will have 50 bytes of data
+        const data = 'x'.repeat(50)
+        insertPromises.push(
+          client.query('INSERT INTO large_result_test(data) VALUES($1)', [data])
+        )
+      }
+
+      // After inserting all rows, attempt to select them all
+      Promise.all(insertPromises)
+        .then(function () {
+          client.on('error', (err) => {
+            // If we see the first error type, mark it
+            if (err.message === 'Query result size exceeded the configured limit') {
+              assert.equal(err.code, 'RESULT_SIZE_EXCEEDED', 'Size exceeded error should have RESULT_SIZE_EXCEEDED code')
+              sizeExceededErrorSeen = true
+            }
+
+            // For the second error type, we just verify it happens after we've seen the first type
+            if (err.message === 'Received unexpected commandComplete message from backend.') {
+              assert(sizeExceededErrorSeen, 'Should have seen size exceeded error before commandComplete error')
+            }
+          })
+
+          // This query should fail due to exceeding size limit
+          client.query('SELECT * FROM large_result_test')
+            .then(function (_result) {
+              throw new Error('Query should have failed due to size limit')
+            })
+            .catch(function (err) {
+              assert.equal(err.code, 'RESULT_SIZE_EXCEEDED', 'Query error should have RESULT_SIZE_EXCEEDED code')
+            })
+        })
+    }))
+  })
+)