Add pytest-cov and .coveragerc (#24778)

Signed-off-by: Reza Barazesh <rezabarazesh@meta.com>

.coveragerc

+[run]
+source = vllm
+omit =
+    */tests/*
+    */test_*
+    */__pycache__/*
+    */build/*
+    */dist/*
+    */vllm.egg-info/*
+    */third_party/*
+    */examples/*
+    */benchmarks/*
+    */docs/*
+
+[report]
+exclude_lines =
+    pragma: no cover
+    def __repr__
+    if self.debug:
+    if settings.DEBUG
+    raise AssertionError
+    raise NotImplementedError
+    if 0:
+    if __name__ == .__main__.:
+    class .*\bProtocol\):
+    @(abc\.)?abstractmethod
+
+[html]
+directory = htmlcov
+
+[xml]
+output = coverage.xml

requirements/test.in

@@ -6,6 +6,7 @@ pytest-asyncio
 pytest-rerunfailures
 pytest-shard
 pytest-timeout
+pytest-cov
 
 # testing utils
 backoff # required for phi4mm test

requirements/test.txt

@@ -135,6 +135,8 @@ colorful==0.5.6
     # via ray
 contourpy==1.3.0
     # via matplotlib
+coverage==7.10.6
+    # via pytest-cov
 cramjam==2.9.0
     # via fastparquet
 cupy-cuda12x==13.6.0
@@ -686,7 +688,9 @@ platformdirs==4.3.6
 plotly==5.24.1
     # via genai-perf
 pluggy==1.5.0
-    # via pytest
+    # via
+    #   pytest
+    #   pytest-cov
 polars==1.29.0
     # via mteb
 pooch==1.8.2
@@ -786,6 +790,7 @@ pytest==8.3.5
     #   buildkite-test-collector
     #   genai-perf
     #   pytest-asyncio
+    #   pytest-cov
     #   pytest-forked
     #   pytest-mock
     #   pytest-rerunfailures
@@ -796,6 +801,8 @@ pytest==8.3.5
     #   terratorch
 pytest-asyncio==0.24.0
     # via -r requirements/test.in
+pytest-cov==6.3.0
+    # via -r requirements/test.in
 pytest-forked==1.6.0
     # via -r requirements/test.in
 pytest-mock==3.14.0