ci: add format and check test (#8)

Signed-off-by: Jérémie Drouet <jeremie.drouet@gmail.com>

.github/workflows/testing.yml

@@ -3,6 +3,17 @@ name: Testing the library
 on: [push]
 
 jobs:
+  format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: nightly
+          profile: minimal
+          components: rustfmt
+      - name: run lint
+        run: cargo fmt --all --check
   test:
     runs-on: ubuntu-latest
     steps:
@@ -16,3 +27,10 @@ jobs:
         uses: actions-rs/cargo@v1
         with:
           command: test
+  check-features:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - uses: taiki-e/install-action@cargo-hack
+      - name: execute lib tests
+        run: cargo hack check --feature-powerset --tests