Convert calibration saving tests to favor json method

Also, catch both user and deprecation warnings for remaining csv
calibration saving tests.

test/calibration/test_calibrations.py

@@ -14,6 +14,7 @@
 
 from test.base import QiskitExperimentsTestCase
 import os
+import unittest
 import uuid
 from collections import defaultdict
 from datetime import datetime, timezone, timedelta
@@ -1617,10 +1618,13 @@ def tearDown(self):
             if os.path.exists(self._prefix + file):
                 os.remove(self._prefix + file)
 
-    def test_save_load_parameter_values(self):
+    def test_save_load_parameter_values_csv(self):
         """Test that we can save and load parameter values."""
+        # NOTE: This is a legacy test that can be removed when csv support is
+        # removed from Calibrations.save
 
-        with self.assertWarns(DeprecationWarning):
+        # Expect user warning about schedules, deprecation warning about csv
+        with self.assertWarns((UserWarning, DeprecationWarning)):
             self.cals.save("csv", overwrite=True, file_prefix=self._prefix)
         self.assertEqual(self.cals.get_parameter_value("amp", (3,), "xp"), 0.1)
 
@@ -1645,11 +1649,11 @@ def test_save_load_parameter_values(self):
         self.assertTrue(isinstance(val, float))
 
         # Check that we cannot rewrite files as they already exist.
-        with self.assertWarns(DeprecationWarning):
-            with self.assertRaises(CalibrationError):
+        with self.assertRaises(CalibrationError):
+            with self.assertWarns((UserWarning, DeprecationWarning)):
                 self.cals.save("csv", file_prefix=self._prefix)
 
-        with self.assertWarns(DeprecationWarning):
+        with self.assertWarns((UserWarning, DeprecationWarning)):
             self.cals.save("csv", overwrite=True, file_prefix=self._prefix)
 
     def test_alternate_date_formats(self):
@@ -1659,13 +1663,10 @@ def test_alternate_date_formats(self):
         value = ParameterValue(0.222, date_time=new_date)
         self.cals.add_parameter_value(value, "amp", (3,), "xp")
 
-        with self.assertWarns(DeprecationWarning):
-            self.cals.save("csv", overwrite=True, file_prefix=self._prefix)
-        self.cals._params = defaultdict(list)
-        with self.assertWarns(DeprecationWarning):
-            self.cals.load_parameter_values(self._prefix + "parameter_values.csv")
+        self.cals.save("json", overwrite=True, file_prefix=self._prefix)
+        self.cals.load(self._prefix + ".json")
 
-    def test_save_load_library(self):
+    def test_save_load_library_csv(self):
         """Test that we can load and save a library.
 
         These libraries contain both parameters with schedules and parameters without
@@ -1678,7 +1679,7 @@ def test_save_load_library(self):
 
         cals.parameters_table()
 
-        with self.assertWarns(DeprecationWarning):
+        with self.assertWarns((UserWarning, DeprecationWarning)):
             cals.save(file_type="csv", overwrite=True, file_prefix=self._prefix)
 
         with self.assertWarns(DeprecationWarning):
@@ -1691,21 +1692,61 @@ def test_save_load_library(self):
             BackendData(backend).drive_freqs[0],
         )
 
+    # Expected to fail because json calibration loading does not support
+    # restoring Parameter objects
+    @unittest.expectedFailure
+    def test_save_load_library(self):
+        """Test that we can load and save a library.
+
+        These libraries contain both parameters with schedules and parameters without
+        any schedules (e.g. frequencies for qubits and readout).
+        """
+
+        library = FixedFrequencyTransmon()
+        backend = FakeArmonkV2()
+        cals = Calibrations.from_backend(backend, libraries=[library])
+
+        cals.parameters_table()
+
+        cals.save(file_type="json", overwrite=True, file_prefix=self._prefix)
+
+        loaded = Calibrations.load(self._prefix + ".json")
+
+        # Test the value of a few loaded params.
+        self.assertEqual(loaded.get_parameter_value("amp", (0,), "x"), 0.5)
+        self.assertEqual(
+            loaded.get_parameter_value("drive_freq", (0,)),
+            BackendData(backend).drive_freqs[0],
+        )
+
     def test_json_round_trip(self):
         """Test round trip test for JSON file format.
 
         This method guarantees full equality including parameterized template schedules
         and we can still generate schedules with loaded calibration instance,
         even though calibrations is instantiated outside built-in library.
         """
-        self.cals.save(file_type="json", overwrite="True", file_prefix=self._prefix)
+        self.cals.save(file_type="json", overwrite=True, file_prefix=self._prefix)
         loaded = self.cals.load(file_path=self._prefix + ".json")
         self.assertEqual(self.cals, loaded)
 
         original_sched = self.cals.get_schedule("cr", (3, 2))
         roundtrip_sched = loaded.get_schedule("cr", (3, 2))
         self.assertEqual(original_sched, roundtrip_sched)
 
+    def test_overwrite(self):
+        """Test that overwriting errors unless overwrite flag is used"""
+        self.cals.save(file_type="json", overwrite=True, file_prefix=self._prefix)
+        with self.assertRaises(CalibrationError):
+            self.cals.save(file_type="json", overwrite=False, file_prefix=self._prefix)
+
+        # Add a value to make sure data is really overwritten and not carried
+        # over from first write
+        self.cals.add_parameter_value(0.45, "amp", (3,), "xp")
+        self.cals.save(file_type="json", overwrite=True, file_prefix=self._prefix)
+        loaded = Calibrations.load(file_path=self._prefix + ".json")
+        self.assertEqual(self.cals, loaded)
+
 
 class TestInstructionScheduleMap(QiskitExperimentsTestCase):
     """Class to test the functionality of a Calibrations"""