continue refactoring to optimize for mtl

mtl/test_params.py

@@ -0,0 +1,20 @@
+import mtl
+from mtl.hypothesis import MetricTemporalLogicStrategy
+
+import hypothesis.strategies as st
+from hypothesis import given
+
+
+@given(st.integers(), st.integers(), st.integers())
+def test_params1(a, b, c):
+    phi = mtl.parse('G[a, b] x')
+    assert {x.name for x in phi.params} == {'a', 'b'}
+
+    phi2 = phi.set_params({'a': a, 'b': b})
+    assert phi2.params == set()
+    assert phi2 == mtl.parse(f'G[{a}, {b}](x)')
+
+
+@given(MetricTemporalLogicStrategy)
+def test_hash_stable(phi):
+    assert hash(phi) == hash(mtl.parse(str(phi)))