remove _advance_time() from benchmark model

- Add a few tests
- Check that for each example model.steps == 10

benchmarks/BoltzmannWealth/boltzmann_wealth.py

@@ -38,7 +38,6 @@ def __init__(self, seed=None, n=100, width=10, height=10):
         self.datacollector.collect(self)
 
     def step(self):
-        self._advance_time()
         self.agents.shuffle().do("step")
         # collect data
         self.datacollector.collect(self)

tests/test_examples.py

@@ -66,3 +66,4 @@ def test_examples(self):
                 model = model_class()
                 for _ in range(10):
                     model.step()
+                self.assertEqual(model.steps, 10)

tests/test_model.py

@@ -9,7 +9,9 @@ def test_model_set_up():
     assert model.current_id == 0
     assert model.current_id + 1 == model.next_id()
     assert model.current_id == 1
+    assert model.steps == 0
     model.step()
+    assert model.steps == 1
 
 
 def test_running():
@@ -18,12 +20,12 @@ class TestModel(Model):
 
         def step(self):
             """Increase steps until 10."""
-            self.steps += 1
             if self.steps == 10:
                 self.running = False
 
     model = TestModel()
     model.run_model()
+    assert model.steps == 10
 
 
 def test_seed(seed=23):