Test substring for quimb objects (quantumlib#5529)

Fixes quantumlib#5524.

Based on quantumlib#5525 discussion, we don't need to pin quimb (yet!), but testing exact strings for quimb objects is asking for trouble. This reduces the tests to substring checks, which should be less vulnerable to minor quimb movements (e.g. this passes with both quimb v1.3.0 and v1.4.0).

Author: 95-martin-orion

cirq/contrib/quimb/mps_simulator_test.py

@@ -266,19 +266,12 @@ def test_trial_result_str():
         prng=value.parse_random_state(0),
         simulation_options=ccq.mps_simulator.MPSOptions(),
     )
-    assert (
-        str(
-            ccq.mps_simulator.MPSTrialResult(
-                params=cirq.ParamResolver({}),
-                measurements={'m': np.array([[1]])},
-                final_simulator_state=final_simulator_state,
-            )
-        )
-        == """measurements: m=1
-output state: TensorNetwork([
-    Tensor(shape=(2,), inds=('i_0',), tags=oset([])),
-])"""
+    result = ccq.mps_simulator.MPSTrialResult(
+        params=cirq.ParamResolver({}),
+        measurements={'m': np.array([[1]])},
+        final_simulator_state=final_simulator_state,
     )
+    assert 'output state: TensorNetwork' in str(result)
 
 
 def test_trial_result_repr_pretty():
@@ -293,40 +286,22 @@ def test_trial_result_repr_pretty():
         measurements={'m': np.array([[1]])},
         final_simulator_state=final_simulator_state,
     )
-    cirq.testing.assert_repr_pretty(
-        result,
-        """measurements: m=1
-output state: TensorNetwork([
-    Tensor(shape=(2,), inds=('i_0',), tags=oset([])),
-])""",
-    )
+    cirq.testing.assert_repr_pretty_contains(result, 'output state: TensorNetwork')
     cirq.testing.assert_repr_pretty(result, "cirq.MPSTrialResult(...)", cycle=True)
 
 
 def test_empty_step_result():
     q0 = cirq.LineQubit(0)
     sim = ccq.mps_simulator.MPSSimulator()
     step_result = next(sim.simulate_moment_steps(cirq.Circuit(cirq.measure(q0))))
-    assert (
-        str(step_result)
-        == """q(0)=0
-TensorNetwork([
-    Tensor(shape=(2,), inds=('i_0',), tags=oset([])),
-])"""
-    )
+    assert 'TensorNetwork' in str(step_result)
 
 
 def test_step_result_repr_pretty():
     q0 = cirq.LineQubit(0)
     sim = ccq.mps_simulator.MPSSimulator()
     step_result = next(sim.simulate_moment_steps(cirq.Circuit(cirq.measure(q0))))
-    cirq.testing.assert_repr_pretty(
-        step_result,
-        """q(0)=0
-TensorNetwork([
-    Tensor(shape=(2,), inds=('i_0',), tags=oset([])),
-])""",
-    )
+    cirq.testing.assert_repr_pretty_contains(step_result, 'TensorNetwork')
     cirq.testing.assert_repr_pretty(step_result, "cirq.MPSSimulatorStepResult(...)", cycle=True)
 
 
@@ -391,13 +366,8 @@ def test_simulate_moment_steps_sample():
                 step._simulator_state().to_numpy(),
                 np.asarray([1.0 / math.sqrt(2), 0.0, 1.0 / math.sqrt(2), 0.0]),
             )
-            assert (
-                str(step)
-                == """TensorNetwork([
-    Tensor(shape=(2,), inds=('i_0',), tags=oset([])),
-    Tensor(shape=(2,), inds=('i_1',), tags=oset([])),
-])"""
-            )
+            # There are two "Tensor()" copies in the string.
+            assert len(str(step).split('Tensor(')) == 3
             samples = step.sample([q0, q1], repetitions=10)
             for sample in samples:
                 assert np.array_equal(sample, [True, False]) or np.array_equal(
@@ -412,13 +382,8 @@ def test_simulate_moment_steps_sample():
                 step._simulator_state().to_numpy(),
                 np.asarray([1.0 / math.sqrt(2), 0.0, 0.0, 1.0 / math.sqrt(2)]),
             )
-            assert (
-                str(step)
-                == """TensorNetwork([
-    Tensor(shape=(2, 2), inds=('i_0', 'mu_0_1'), tags=oset([])),
-    Tensor(shape=(2, 2), inds=('mu_0_1', 'i_1'), tags=oset([])),
-])"""
-            )
+            # There are two "Tensor()" copies in the string.
+            assert len(str(step).split('Tensor(')) == 3
             samples = step.sample([q0, q1], repetitions=10)
             for sample in samples:
                 assert np.array_equal(sample, [True, True]) or np.array_equal(

cirq/testing/__init__.py

@@ -92,6 +92,10 @@
     random_two_qubit_circuit_with_czs,
 )
 
-from cirq.testing.repr_pretty_tester import assert_repr_pretty, FakePrinter
+from cirq.testing.repr_pretty_tester import (
+    assert_repr_pretty,
+    assert_repr_pretty_contains,
+    FakePrinter,
+)
 
 from cirq.testing.sample_circuits import nonoptimal_toffoli_circuit

cirq/testing/repr_pretty_tester.py

@@ -53,3 +53,22 @@ def assert_repr_pretty(val: Any, text: str, cycle: bool = False):
     p = FakePrinter()
     val._repr_pretty_(p, cycle=cycle)
     assert p.text_pretty == text, f"{p.text_pretty} != {text}"
+
+
+def assert_repr_pretty_contains(val: Any, substr: str, cycle: bool = False):
+    """Assert that the given object has a `_repr_pretty_` output that contains the given text.
+
+    Args:
+            val: The object to test.
+            substr: The string that `_repr_pretty_` is expected to contain.
+            cycle: The value of `cycle` passed to `_repr_pretty_`.  `cycle` represents whether
+                the call is made with a potential cycle. Typically one should handle the
+                `cycle` equals `True` case by returning text that does not recursively call
+                the `_repr_pretty_` to break this cycle.
+
+    Raises:
+        AssertionError: If `_repr_pretty_` does not pretty print the given text.
+    """
+    p = FakePrinter()
+    val._repr_pretty_(p, cycle=cycle)
+    assert substr in p.text_pretty, f"{substr} not in {p.text_pretty}"

cirq/testing/repr_pertty_tester_test.py renamed to cirq/testing/repr_pretty_tester_test.py

@@ -42,3 +42,23 @@ def _repr_pretty_(self, p, cycle):
 
     cirq.testing.assert_repr_pretty(TestClassMultipleTexts(), "I'm so pretty I am")
     cirq.testing.assert_repr_pretty(TestClassMultipleTexts(), "TestClass", cycle=True)
+
+
+def test_assert_repr_pretty_contains():
+    class TestClass:
+        def _repr_pretty_(self, p, cycle):
+            p.text("TestClass" if cycle else "I'm so pretty")
+
+    cirq.testing.assert_repr_pretty_contains(TestClass(), "pretty")
+    cirq.testing.assert_repr_pretty_contains(TestClass(), "Test", cycle=True)
+
+    class TestClassMultipleTexts:
+        def _repr_pretty_(self, p, cycle):
+            if cycle:
+                p.text("TestClass")
+            else:
+                p.text("I'm so pretty")
+                p.text(" I am")
+
+    cirq.testing.assert_repr_pretty_contains(TestClassMultipleTexts(), "I am")
+    cirq.testing.assert_repr_pretty_contains(TestClassMultipleTexts(), "Class", cycle=True)