chore: extra coverage args via env var.

Author: Zhe Yu

Makefile

@@ -1,5 +1,6 @@
 EXTRA_LOCK_ARGS?=
 EXTRA_DEPS?=
+EXTRA_COVERAGEPY_ARGS?=
 
 LOADED_DOT_ENV=@if [ -f .env ] ; then source .env; fi;
 
@@ -24,7 +25,7 @@ multitest:
 
 coverage:
 	make deps; \
-	pdm run coverage run -m pytest; \
+	pdm run coverage run $(EXTRA_COVERAGEPY_ARGS) -m pytest; \
 	pdm run coverage html; \
 	pdm run coverage report -m
 

docs/CONTRIBUTING.md

@@ -66,6 +66,15 @@ Please take a look at [the database documentation](../src/vectorcode/database/RE
 which contains a brief introduction on the API design that explains what you'd need 
 to do to add support for a new database.
 
+### Coverage Across Mutiple Runs
+
+If, for some reasons, you need to run the tests multiple times to get full coverage 
+(maybe when there are conflicting dependency groups like chromadb 0.6.3 vs chromadb 1.x), you can pass `--append` flag to the `coverage` command.
+If you're using `make coverage`, you can set this flag via the `EXTRA_COVERAGEPY_ARGS` environment variable:
+```bash 
+EXTRA_COVERAGEPY_ARGS="--append" make coverage
+```
+
 ## Neovim Plugin
 
 At the moment, there isn't much to cover on here. As long as the code is