build: Use nextest cargo test runner in CI

Supports retries for flaky failures. Use 3 retries.
Also limit the db test to run in a separate process, so that
diesel_migration harness doesn't fail with an I/O error.

.config/nextest.toml

@@ -0,0 +1,16 @@
+[profile.ci]
+# Don't fail fast in CI to run the full test suite.
+fail-fast = false
+failure-output = "immediate-final"
+retries = 3
+
+[test-groups]
+serial-integration = { max-threads = 1 }
+
+[[profile.default.overrides]]
+filter = 'test(db::logic::tests::test_do_ops_with_db)'
+test-group = 'serial-integration'
+
+[[profile.ci.overrides]]
+filter = 'test(db::logic::tests::test_do_ops_with_db)'
+test-group = 'serial-integration'

.github/workflows/ci.yaml

@@ -164,8 +164,11 @@ jobs:
       - name: Create dummy web artifacts
         run: mkdir -p webclients/svelte/build
 
-      - name: Run cargo test
-        run: cargo test ${{ matrix.features && '--features' }} ${{ matrix.features }} ${{ matrix.release && '--release' || '' }} ${{ matrix.no_default_features && '--no-default-features' || '' }} ${{ matrix.all_features && '--all-features' || '' }}
+      - name: Install latest nextest release
+        uses: taiki-e/install-action@nextest
+
+      - name: Run cargo nextest
+        run: cargo nextest run --profile ci ${{ matrix.features && '--features' }} ${{ matrix.features }} ${{ matrix.release && '--release' || '' }} ${{ matrix.no_default_features && '--no-default-features' || '' }} ${{ matrix.all_features && '--all-features' || '' }}
         env:
           RUST_BACKTRACE: full