Start adding more tests for benchmark task

tests/unit/amlb/resources/test_benchmark_definition.py

@@ -112,17 +112,33 @@ def test_add_task_defaults_looks_up_instance_type(amlb_dummy_configuration: Name
     ), "Should not overwrite explicit configuration"
 
 
-def test_benchmark_task(load_default_resources: Resources):
+def create_benchmark_task(resources: Resources, task: Namespace):
     benchmark = Benchmark(
         framework_name="constantpredictor",
         benchmark_name="test",
         constraint_name="test",
         job_history=None,
     )
-    task = Namespace(name="foo")
-    Resources._add_task_defaults(task, load_default_resources.config)
-    benchmark_task = BenchmarkTask(
+    Resources._add_task_defaults(task, resources.config)
+    return BenchmarkTask(
         benchmark=benchmark,
         task_def=task,
         fold=0,
     )
+
+
+def test_benchmark_task_load_data_raises_if_no_dataset(load_default_resources):
+    task = Namespace(name="foo")
+    benchmark_task = create_benchmark_task(load_default_resources, task)
+
+    with pytest.raises(ValueError) as excinfo:
+        benchmark_task.load_data()
+    assert "should have one property" in excinfo.value.args[0]
+
+
+def test_benchmark_task_load_data(load_default_resources, mocker):
+    task = Namespace(name="foo", openml_task_id=42)
+    benchmark_task = create_benchmark_task(load_default_resources, task)
+
+    mocker.patch("amlb.benchmark.Benchmark.data_loader.load", return_value={})
+    benchmark_task.load_data()