finalize implementation

Author: maxbachmann

.gitattributes

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+tests/test_cydifflib_expect.html linguist-vendored

.github/FUNDING.yml

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+github: maxbachmann

.github/workflows/branchbuild.yml

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+name: Build
+
+on:
+  push:
+    branches-ignore:
+      - main
+
+jobs:
+  tests:
+    name: "Python ${{ matrix.python-version }}"
+    runs-on: "ubuntu-latest"
+    strategy:
+      matrix:
+        python-version: ["3.6", "3.9", "3.10"]
+        os: [ubuntu-latest, windows-latest, macos-latest]
+
+    steps:
+      - uses: "actions/checkout@v2"
+        with:
+          submodules: 'true'
+      - uses: "actions/setup-python@v2"
+        with:
+          python-version: "${{ matrix.python-version }}"
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install pytest
+
+      - name: build
+        run: |
+          pip install build; python -m build --sdist
+          # test whether tarball contains all files required for compiling
+          pip install dist/cydifflib-*.tar.gz
+
+      - name: Test with pytest
+        run: |
+          pytest tests