TmpDir: add serialize utilities (#6620)

tests/func/experiments/test_experiments.py

@@ -8,7 +8,7 @@ from funcy import first
 
 from dvc.dvcfile import PIPELINE_FILE
 from dvc.repo.experiments.utils import exp_refs_by_rev
-from dvc.utils.serialize import PythonFileCorruptedError, load_yaml
+from dvc.utils.serialize import PythonFileCorruptedError
 from tests.func.test_repro_multistage import COPY_SCRIPT
 
 
@@ -660,9 +660,9 @@ def test_modified_data_dep(tmp_dir, scm, dvc, workspace, params, target):
 
 
 def test_exp_run_recursive(tmp_dir, scm, dvc, run_copy_metrics):
-    tmp_dir.dvc_gen("metric_t.json", "foo: 1")
+    tmp_dir.dvc_gen("metric_t.json", '{"foo": 1}')
     run_copy_metrics(
         "metric_t.json", "metric.json", metrics=["metric.json"], no_exec=True
     )
     assert dvc.experiments.run(".", recursive=True)
-    assert load_yaml(tmp_dir / "metric.json") == {"foo": 1}
+    assert (tmp_dir / "metric.json").parse() == {"foo": 1}