fix coverage

Author: rmorshea

src/idom/client/_private.py

@@ -16,14 +16,22 @@
 IDOM_CLIENT_IMPORT_SOURCE_URL_INFIX = "/_snowpack/pkg"
 
 
-if not IDOM_CLIENT_BUILD_DIR.current.exists():
-    # populate the runtime build directory if it doesn't exist
-    shutil.copytree(BACKUP_BUILD_DIR, IDOM_CLIENT_BUILD_DIR.current, symlinks=True)
-elif getmtime(BACKUP_BUILD_DIR) > getmtime(IDOM_CLIENT_BUILD_DIR.current):
-    # delete the existing runtime build because it's out of date
-    shutil.rmtree(IDOM_CLIENT_BUILD_DIR.current)
-    # replace it with the newer backup build (presumable from a fresh install)
-    shutil.copytree(BACKUP_BUILD_DIR, IDOM_CLIENT_BUILD_DIR.current, symlinks=True)
+def _run_build_dir_init_only_once():  # pragma: no cover
+    """Initialize the runtime build directory
+
+    This should only be called *once*
+    """
+    if not IDOM_CLIENT_BUILD_DIR.current.exists():
+        # populate the runtime build directory if it doesn't exist
+        shutil.copytree(BACKUP_BUILD_DIR, IDOM_CLIENT_BUILD_DIR.current, symlinks=True)
+    elif getmtime(BACKUP_BUILD_DIR) > getmtime(IDOM_CLIENT_BUILD_DIR.current):
+        # delete the existing runtime build because it's out of date
+        shutil.rmtree(IDOM_CLIENT_BUILD_DIR.current)
+        # replace it with the newer backup build (presumable from a fresh install)
+        shutil.copytree(BACKUP_BUILD_DIR, IDOM_CLIENT_BUILD_DIR.current, symlinks=True)
+
+
+_run_build_dir_init_only_once()  # this is only ever called once!
 
 
 def get_user_packages_file(app_dir: Path) -> Path: