Interpret paths relative to config file instead of cwd (#237)

Previously, the server root and the benchmark paths were interpreted relative to the current working directory. This meant that a given config could only ever run from one specific working directory, which was confusing and inconvenient. Now, they are interpreted relative to the config file path itself, so the current directory doesn't matter.

Also:

- Update package locks
- Remove outdated chromedriver pinning in CI
- Upgraded CI to Node 16 and the latest versions of the checkout/node actions

Fixes #176

.github/workflows/tests.yaml

@@ -13,25 +13,19 @@ jobs:
             browsers: chrome-headless, firefox-headless
 
           - job: macos
-            # Note macos-11 is currently more recent than macos-latest
-            # https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#github-hosted-runners
-            os: macos-11
+            os: macos-12
             browsers: safari
 
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
-          node-version: 14
+          node-version: 16
           cache: npm
 
       - run: npm ci
-      # TODO(aomarks) The latest chromedriver has updated to 94, but GitHub
-      # Actions hasn't updated yet. Pin to the earlier verison of chromedriver
-      # until GitHub Actions updated.
-      - run: npm install chromedriver@^93.0.0
       - run: npm run build
 
       - run: npm test
@@ -42,21 +36,21 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
-          node-version: 14
+          node-version: 16
           cache: npm
       - run: npm ci
       - run: npm run lint
 
   check-format:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
-          node-version: 14
+          node-version: 16
           cache: npm
       - run: npm ci
       - run: npm run format:check

CHANGELOG.md

@@ -5,7 +5,37 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/) and this
 project adheres to [Semantic Versioning](http://semver.org/).
 
-<!-- ## Unreleased -->
+## Unreleased
+
+- [**BREAKING**] Benchmark and `root` paths are now interpreted relative to the
+  location of the config file, instead of the current working directory.
+
+  For example, a config at path `<repo>/benchmarks/foo/tachometer.json` that
+  used to look as follows, and had to be run with `<repo>` as the cwd:
+
+  ```json
+  {
+    "root": ".",
+    "benchmarks": [
+      {
+        "url": "benchmarks/foo/index.html"
+      }
+    ]
+  }
+  ```
+
+  Should now look like this, and can be run from any cwd:
+
+  ```json
+  {
+    "root": "../..",
+    "benchmarks": [
+      {
+        "url": "foo.html"
+      }
+    ]
+  }
+  ```
 
 ## [0.5.10] 2021-09-27
 

README.md

@@ -742,9 +742,18 @@ performance isolation.
 Use the `--config` flag to control tachometer with a JSON configuration file.
 Defaults are the same as the corresponding command-line flags.
 
+All paths in a config file are relative to the path of the config file itself.
+
+You will typically want to set `root` to the directory that contains your
+package's `node_modules/` folder, so that the web server will be able to resolve
+bare-module imports.
+
+For example, a file called `benchmarks/foo/tachometer.json` might look like
+this:
+
 ```json
 {
-  "root": "./benchmarks",
+  "root": "../..",
   "sampleSize": 50,
   "timeout": 3,
   "autoSampleConditions": ["0%", "1%"],