refactor: Migrates Python tests to pytest (#413)

* Migrates test_api.py to pytest

Migrates test_api.py to pytest and removes `unittest`. Changes setup functions
to fixtures and replaces `unittest` assertion methods with regular Python `assert`s.

Also lowers the timeout for the server to make the tests run a bit faster.

* Updates test_binding.py to use pytest

Replaces all `unittest` APIs with equivalent `pytest` ones. This change
also updates the tests to use `tempfile` instead of manually creating and
removing files and directories.

* Parametrizes tests instead of running loops

* Updates L0 job to free space on host

.github/workflows/build-and-test.yml

@@ -14,15 +14,27 @@ jobs:
       image: nvcr.io/nvidia/tritonserver:24.10-py3
       volumes:
         - ${{ github.workspace }}:/core
+        # Mount /usr so we can free space
+        - /usr:/host_usr
+      env:
+        AGENT_TOOLSDIRECTORY: "$AGENT_TOOLSDIRECTORY"
 
     steps:
       - uses: actions/checkout@v3
 
+      - name: Free space
+        run: |
+          rm -rf \
+            /host_usr/share/dotnet /host_usr/local/lib/android /opt/ghc \
+            /host_usr/local/share/powershell /host_usr/share/swift /host_usr/local/.ghcup \
+            /host_usr/lib/jvm
+          rm -rf "$AGENT_TOOLSDIRECTORY"
+
       - name: Install dependencies
         run: |
           apt update
           apt install -y --no-install-recommends clang-format-15 cmake libb64-dev rapidjson-dev libre2-dev
-          wget -O /tmp/boost.tar.gz https://archives.boost.io/release/1.80.0/source/boost_1_80_0.tar.gz && (cd /tmp && tar xzf boost.tar.gz) && mv /tmp/boost_1_80_0/boost /usr/include/boost
+          wget -O /tmp/boost.tar.gz https://archives.boost.io/release/1.80.0/source/boost_1_80_0.tar.gz && (cd /tmp && tar xzf boost.tar.gz) && mv /tmp/boost_1_80_0/boost /usr/include/boost && rm /tmp/boost.tar.gz
           pip install build pytest
 
       - name: Build