fix: allow python tests to use custom repo

CONTRIBUTING.md

@@ -239,6 +239,15 @@ ${FTL_HOME}/build/release/ftl dev
 ```
 where `FTL_HOME` is the root of this repository.
 
+## Building Python with a custom artifact repository
+
+In order to run the tests with a custom python artifact repository you need to run:
+
+`export PYTHON_REPOSITORY=<your-private-repo>`
+
+The tests on `compile/build_test.go` will use this to run `uv --index $PYTHON_REPOSITORY --native-tls` which
+should get the tests to pass.
+
 ## Useful links
 
 - [VSCode extension samples](https://github.com/microsoft/vscode-extension-samples)

python-runtime/compile/build_test.go

@@ -20,7 +20,12 @@ func TestBuild(t *testing.T) {
 	assert.NoError(t, err)
 	ctx := log.ContextWithNewDefaultLogger(context.Background())
 	assert.NoError(t, os.RemoveAll(filepath.Join(moduleDir, ".venv")))
-	assert.NoError(t, exec.Command(ctx, log.Debug, moduleDir, "uv", "sync").Run())
+	env := os.Getenv("PYTHON_REPOSITORY")
+	args := []string{"sync"}
+	if env != "" {
+		args = append(args, "--index", env, "--native-tls")
+	}
+	assert.NoError(t, exec.Command(ctx, log.Debug, moduleDir, "uv", args...).Run())
 
 	t.Run("schema extraction", func(t *testing.T) {
 		config := moduleconfig.AbsModuleConfig{