diff --git a/pyproject.toml b/pyproject.toml
index 136ebfe6d..4503ec1cd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -212,7 +212,7 @@ commands = [["bandit", "-r", "src/borg", "-c", "pyproject.toml"]]
 [tool.coverage.run]
 branch = true
 disable_warnings = ["module-not-measured", "no-ctracer"]
-source = "src/borg"
+source = ["src/borg"]
 omit = [
     "*/borg/__init__.py",
     "*/borg/__main__.py",
diff --git a/requirements.d/development.lock.txt b/requirements.d/development.lock.txt
index 832510985..fe384c1de 100644
--- a/requirements.d/development.lock.txt
+++ b/requirements.d/development.lock.txt
@@ -8,6 +8,7 @@ pkgconfig==1.5.5
 tox==4.26.0
 pytest==8.4.0
 pytest-xdist==3.7.0
+coverage[toml]==7.9.1
 pytest-cov==6.2.1
 pytest-benchmark==5.1.0
 Cython==3.1.2
diff --git a/requirements.d/development.txt b/requirements.d/development.txt
index 10d7b55bf..1c2a409fd 100644
--- a/requirements.d/development.txt
+++ b/requirements.d/development.txt
@@ -8,6 +8,7 @@ pkgconfig
 tox
 pytest
 pytest-xdist
+coverage[toml]
 pytest-cov
 pytest-benchmark
 Cython