nginx-tests: eliminate duplicate dockerfile

pros:

* nginx tests actually run against a real image

cons:

* slows fresh/CI builds by about 1 minute

.github/workflows/test-nginx.yml

@@ -10,6 +10,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+        fetch-tags: true
+        submodules: recursive
     - uses: actions/setup-node@v4
       with:
         node-version: 20.17.0

test/nginx.test.docker-compose.yml

@@ -16,7 +16,7 @@ services:
   nginx:
     build:
       context: ..
-      dockerfile: ./test/nginx-test.dockerfile
+      dockerfile: nginx.dockerfile
     depends_on:
       - service
       - enketo

test/run-tests.sh

@@ -26,11 +26,6 @@ wait_for_http_response() {
   fi  
 }
 
-log "Checking nginx dockerfiles have same base image..."
-# It would be nice if Dockerfiles allowed some kind of templating which would
-# allow for direct sharing between the real and test nginx dockerfiles.
-diff <(grep FROM nginx-test.dockerfile) <(grep FROM ../nginx.dockerfile | grep -v AS)
-
 log "Starting test services..."
 docker_compose up --build --detach
 

test/test-nginx.js

@@ -47,23 +47,25 @@ describe('nginx config', () => {
   });
 
   [
-    '/index.html',
-    '/version.txt',
-  ].forEach(staticFile => {
+    [ '/index.html',  /<div id="app"><\/div>/ ],
+    [ '/version.txt', /^versions:/ ],
+  ].forEach(([ staticFile, expectedContent ]) => {
     it(`${staticFile} file should have no-cache header`, async () => {
       // when
       const res = await fetchHttps(staticFile);
 
       // then
       assert.isTrue(res.ok);
       assert.equal(res.status, 200);
-      assert.equal(await res.text(), `hi:${staticFile}\n`);
+      assert.match(await res.text(), expectedContent);
       assert.equal(await res.headers.get('cache-control'), 'no-cache');
     });
   });
 
   [
-    '/should-be-cached.txt',
+    '/blank.html',
+    '/favicon.ico',
+    // there's no way to predict generated asset paths, as they have cache-busting names
   ].forEach(staticFile => {
     it(`${staticFile} file should not have no-cache header`, async () => {
       // when
@@ -72,7 +74,6 @@ describe('nginx config', () => {
       // then
       assert.isTrue(res.ok);
       assert.equal(res.status, 200);
-      assert.equal(await res.text(), `hi:${staticFile}\n`);
       assert.isNull(await res.headers.get('cache-control'));
     });
   });