Bugfix for non deterministic rng behavior (#2598)

* bugfix

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: quaquel

mesa/model.py

@@ -94,7 +94,7 @@ def __init__(
             self._seed = seed  # this allows for reproducing stdlib.random
 
             try:
-                self.rng: np.random.Generator = np.random.default_rng(rng)
+                self.rng: np.random.Generator = np.random.default_rng(seed)
             except TypeError:
                 rng = self.random.randint(0, sys.maxsize)
                 self.rng: np.random.Generator = np.random.default_rng(rng)

tests/test_model.py

@@ -1,5 +1,7 @@
 """Tests for model.py."""
 
+import numpy as np
+
 from mesa.agent import Agent, AgentSet
 from mesa.model import Model
 
@@ -37,6 +39,16 @@ def test_seed(seed=23):
     assert model2._seed == seed + 1
     assert model._seed == seed
 
+    assert Model(seed=42).random.random() == Model(seed=42).random.random()
+    assert np.all(
+        Model(seed=42).rng.random(
+            10,
+        )
+        == Model(seed=42).rng.random(
+            10,
+        )
+    )
+
 
 def test_reset_randomizer(newseed=42):
     """Test resetting the random seed on the model."""