diff --git a/pyproject.toml b/pyproject.toml
index ccd10cb871..77e7d6bf1b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,6 +18,7 @@ starcraft-hello = "starcraft:hello"
 
 [project.optional-dependencies]
 dev = [
+    "coverage[toml]==7.1.0",
     "pytest==7.2.1",
     "pytest-cov==4.0.0",
     "pytest-mock==3.10.0",
diff --git a/tox.ini b/tox.ini
index 4f7d43f6f9..9c644856ce 100644
--- a/tox.ini
+++ b/tox.ini
@@ -26,9 +26,10 @@ user_tmp_dir = {env:TMPDIR}
 env_tmp_dir = {user_tmp_dir:{env:XDG_RUNTIME_DIR:{work_dir}}}/tox_tmp/{env_name}
 set_env =
     TMPDIR={env_tmp_dir}
+    COVERAGE_FILE={env_tmp_dir}/.coverage_{env_name}
 
 [test]  # Base configuration for unit and integration tests
-package = sdist
+package = editable
 extras = dev
 allowlist_externals = mkdir
 commands_pre = mkdir -p results
@@ -38,9 +39,6 @@ base = testenv, test
 description = Run unit tests with pytest
 labels =
     py38, py310, py311: tests, unit-tests
-set_env =
-    TMPDIR={env_tmp_dir}
-    COVERAGE_FILE=.coverage_{env_name}
 commands = pytest {tty:--color=yes} --cov --cov-report=xml:results/coverage-{env_name}.xml --junit-xml=results/test-results-{env_name}.xml tests/unit {posargs}
 
 [testenv:integration-{py38,py39,py310,py311,py312}]