feat(QA): add test cases for websteps vs webconnectivity (#583)

This pull request introduces a set of Node.js scripts for performing A/B comparison of websteps and webconnectivity as described in https://github.com/ooni/probe/issues/1805. Rather than using Jafar, I ended up using `miniooni`'s `--censor` command line flag introduced in [v3.12.0-alpha.1](https://github.com/ooni/probe-cli/releases/tag/v3.12.0-alpha.1). The main reason for doing so is that it's simpler to run tests without requiring root access and Linux _and_ Docker (e.g., I did not develop part of this diff using Linux). Additionally, I choose to use Node.js rather than extending the existing Python framework for QA, because I found Node.js easier when working with JSON data.

QA/index.mjs

@@ -0,0 +1,106 @@
+// This script performs QA checks.
+
+import { runTestCase } from "./lib/runner.mjs"
+import { testCases as webTestCases } from "./lib/web.mjs"
+
+// testCases lists all the test cases.
+//
+// A test case is an object with the structure described
+// by the documentation of runTestCase in ./lib/runner.mjs.
+const testCases = [
+    ...webTestCases,
+]
+
+// checkForDuplicateTestCases ensures there are no duplicate names.
+function checkForDuplicateTestCases() {
+    let dups = {}
+    for (let i = 0; i < testCases.length; i++) {
+        const testCase = testCases[i]
+        if (dups[testCase.name] !== undefined) {
+            console.log(`fatal: duplicate test case name: ${testCase.name}`)
+            process.exit(1)
+        }
+        dups[testCase.name] = true
+    }
+}
+
+// runAllTestCases runs all the available test cases.
+function runAllTestCases() {
+    let result = true
+    for (let i = 0; i < testCases.length; i++) {
+        result = result && runTestCase(testCases[i])
+    }
+    return result
+}
+
+// makeTestCasesMap creates a map from the test case name
+// to the test case definition.
+function makeTestCasesMap() {
+    var map = {}
+    for (let i = 0; i < testCases.length; i++) {
+        const testCase = testCases[i]
+        map[testCase.name] = testCase
+    }
+    return map
+}
+
+// commandRun implements the run command.
+function commandRun(args) {
+    const bailOnFailure = (result) => {
+        if (!result) {
+            console.log("some checks failed (see above logs)")
+            process.exit(1)
+        }
+    }
+    if (args.length < 1) {
+        bailOnFailure(runAllTestCases())
+        return
+    }
+    let result = true
+    const map = makeTestCasesMap()
+    for (let i = 0; i < args.length; i++) {
+        const arg = args[i]
+        const testCase = map[arg]
+        if (testCase === undefined) {
+            console.log(`unknown test case: ${arg}`)
+            process.exit(1)
+        }
+        result = result && runTestCase(testCase)
+    }
+    bailOnFailure(result)
+}
+
+// commandList implements the list command.
+function commandList() {
+    for (let i = 0; i < testCases.length; i++) {
+        const testCase = testCases[i]
+        console.log(`${testCase.name}: ${testCase.description}`)
+    }
+}
+
+// main is the main function.
+function main() {
+    const usageAndExit = (exitcode) => {
+        console.log("usage: node ./QA/index.mjs list")
+        console.log("usage: node ./QA/index.mjs run [test_case_name...]")
+        process.exit(exitcode)
+    }
+    if (process.argv.length < 3) {
+        usageAndExit(0)
+    }
+    checkForDuplicateTestCases()
+    const command = process.argv[2]
+    switch (command) {
+        case "list":
+            commandList()
+            break
+        case "run":
+            commandRun(process.argv.slice(3))
+            break
+        default:
+            console.log(`unknown command: ${command}`)
+            usageAndExit(1)
+    }
+}
+
+main()