feat(bazel/integration): support tracking sizes within the integration test rule directly

bazel/integration/test_runner/BUILD.bazel

@@ -8,6 +8,7 @@ ts_project(
     tsconfig = "//bazel:tsconfig",
     deps = [
         "//bazel:node_modules/@types/node",
+        "//bazel:node_modules/chalk",
         "//bazel:node_modules/true-case-path",
     ],
 )

bazel/integration/test_runner/runner.mts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {existsSync} from 'node:fs';
 import fs from 'node:fs/promises';
 import path from 'node:path';
 import os from 'node:os';
@@ -30,6 +31,14 @@ import {
 } from './process_utils.mjs';
 import {ENVIRONMENT_TMP_PLACEHOLDER} from './constants.mjs';
 import {debug} from './debug.mjs';
+import chalk from 'chalk';
+
+// Convience access to chalk colors.
+const {red, green} = chalk;
+/** The size discrepancy we allow in bytes. */
+const THRESHOLD_BYTES = 5000;
+/** The size discrepancy as a percentage. */
+const THRESHOLD_PERCENT = 5;
 
 /** Error class that is used when an integration command fails.  */
 class IntegrationTestCommandError extends Error {}
@@ -270,6 +279,11 @@ export class TestRunner {
     console.info(
       `Successfully ran all commands in test directory: ${path.normalize(testWorkingDir)}`,
     );
+
+    // If the integration test provides a size.json file we use it as a size tracking marker.
+    if (existsSync(path.join(testWorkingDir, 'size.json'))) {
+      await this._runSizeTracking(testWorkingDir, commandEnv);
+    }
   }
 
   /**
@@ -299,4 +313,98 @@ export class TestRunner {
 
     return {...defaults, ...baseEnv};
   }
+
+  /**
+   * Runs the size tracking scripting.
+   *
+   * Builds the integration test application and then checks if the size of the generated files varies too
+   * far from our known file sizes.
+   */
+  private async _runSizeTracking(
+    testWorkingDir: string,
+    commandEnv: NodeJS.ProcessEnv,
+  ): Promise<void> {
+    const success = await runCommandInChildProcess('yarn', ['build'], testWorkingDir, commandEnv);
+    if (!success) {
+      throw Error('Failed to build for size tracking.');
+    }
+
+    const sizes: {[key: string]: SizeCheckResult} = {};
+
+    const expectedSizes = JSON.parse(
+      await fs.readFile(path.join(testWorkingDir, 'size.json'), 'utf-8'),
+    ) as {[key: string]: number};
+
+    for (let [filename, expectedSize] of Object.entries(expectedSizes)) {
+      const generedFilePath = path.join(testWorkingDir, 'dist', filename);
+      if (!existsSync(generedFilePath)) {
+        sizes[filename] = {
+          actual: undefined,
+          failing: false,
+          expected: expectedSize,
+          details: 'missing',
+        };
+      } else {
+        const {size: actualSize} = await fs.stat(path.join(testWorkingDir, 'dist', filename));
+        const absoluteSizeDiff = Math.abs(actualSize - expectedSize);
+        const percentSizeDiff = (absoluteSizeDiff / expectedSize) * 100;
+        const direction = actualSize === expectedSize ? '' : actualSize > expectedSize ? '+' : '-';
+        sizes[filename] = {
+          actual: actualSize,
+          expected: expectedSize,
+          failing: absoluteSizeDiff > THRESHOLD_BYTES || percentSizeDiff > THRESHOLD_PERCENT,
+          details: {
+            raw: `${direction}${absoluteSizeDiff.toFixed(0)}`,
+            percent: `${direction}${percentSizeDiff.toFixed(3)}`,
+          },
+        };
+      }
+    }
+
+    console.info(Array(80).fill('=').join(''));
+    console.info(
+      `${Array(28).fill('=').join('')} SIZE TRACKING RESULTS ${Array(29).fill('=').join('')}`,
+    );
+    console.info(Array(80).fill('=').join(''));
+    let failed = false;
+    for (let [filename, {actual, expected, failing, details}] of Object.entries(sizes)) {
+      failed = failed || failing;
+      const bullet = failing ? green('✔') : red('✘');
+      console.info(`  ${bullet} ${filename}`);
+      if (details === 'missing') {
+        console.info(
+          `      File not found in generated integration test application, either ensure the file is created or remove it from the size tracking json file.`,
+        );
+      } else {
+        console.info(
+          `      Actual Size: ${actual} | Expected Size: ${expected} | ${details.raw} bytes (${details.raw}%)`,
+        );
+      }
+    }
+    console.info();
+    if (failed) {
+      const sizeFileLocation = path.join(this.testPackage, 'size.json');
+      console.info(
+        `If this is a desired change, please update the size limits in: ${sizeFileLocation}`,
+      );
+      process.exitCode = 1;
+    } else {
+      console.info(
+        `Payload size check passed. All diffs are less than ${THRESHOLD_PERCENT}% or ${THRESHOLD_BYTES} bytes.`,
+      );
+    }
+    console.info(Array(80).fill('=').join(''));
+  }
+}
+
+interface SizeCheckResult {
+  expected: number;
+  actual: number | undefined;
+  failing: boolean;
+  details:
+    | 'missing'
+    | {
+        raw: string;
+        percent: string;
+      };
 }

bazel/package.json

@@ -9,6 +9,7 @@
     "@types/wait-on": "^5.3.4",
     "@types/yargs": "17.0.33",
     "browser-sync": "3.0.4",
+    "chalk": "5.4.1",
     "piscina": "^5.0.0",
     "send": "1.2.0",
     "true-case-path": "2.2.1",