run tests in parallel, only collect coverage on ubuntu

.github/scripts/integration_test_runner.sh

@@ -0,0 +1,8 @@
+# setup hardhat for compilation tests
+pushd tests/e2e/compilation/test_data/test_node_modules/
+npm install hardhat
+popd
+
+# used to pass --cov=$path and --cov-append to pytest
+pytest $1 tests/e2e/ -n auto
+python -m coverage report

.github/scripts/tool_test_runner.sh

@@ -0,0 +1,4 @@
+npm install --global ganache
+# used to pass --cov=$path and --cov-append to pytest
+pytest $1 tests/tools/read-storage/test_read_storage.py
+python -m coverage report

.github/scripts/unit_test_runner.sh

@@ -0,0 +1,3 @@
+# used to pass --cov=$path and --cov-append to pytest
+pytest $1 tests/unit/
+python -m coverage report

.github/workflows/test.yml

@@ -24,6 +24,7 @@ jobs:
       fail-fast: false
       matrix:
         os: ["ubuntu-latest", "windows-2022"]
+        type: ["unit", "integration", "tool"]
     steps:
       - uses: actions/checkout@v3
       - name: Set up Python 3.8
@@ -36,34 +37,18 @@ jobs:
           solc-select install 0.8.0
           solc-select use 0.8.0
 
-      - name: e2e / detectors
+      - name: ${{ matrix.type }}
+        env:
+          TEST_TYPE: ${{ matrix.type }}
+        # Only run coverage on ubuntu-latest.
         run: |
-          pytest --cov=slither --cov-append tests/e2e/detectors/test_detectors.py -n auto
-          python -m coverage report
+          if [ ${{ matrix.os }} = "ubuntu-latest" ]; then
+            TEST_ARGS="--cov=slither --cov-append"
+          elif [ ${{ matrix.os }} = "windows-2022" ]; then
+            TEST_ARGS=""
+          fi
+          bash "./.github/scripts/${TEST_TYPE}_test_runner.sh"
 
-      - name: e2e / ast parsing
-        run: |
-          pytest --cov=slither --cov-append tests/e2e/solc_parsing/test_ast_parsing.py -n auto
-          python -m coverage report
-
-      - name: e2e / compilation
-        run: |
-          pushd tests/e2e/compilation/test_data/test_node_modules/
-          npm install hardhat
-          popd
-          pytest --cov=slither --cov-append tests/e2e/compilation/
-          python -m coverage report
-
-      - name: unit / core, slithir, utils 
-        run: |
-          pytest --cov=slither --cov-append tests/unit/
-          python -m coverage report
-
-      - name: tools / slither-read-storage
-        run: |
-          npm install --global ganache
-          pytest --cov=slither --cov-append tests/tools/read-storage/test_read_storage.py
-          python -m coverage report
 
       - uses: ./.github/actions/upload-coverage
         # only aggregate test coverage over linux-based tests to avoid any OS-specific filesystem information stored in