Only send 0 or 1 to two-step parameters below strictness level 8

Some plugins keep in-between values for on/off parameters rather than
mapping them to a step (e.g. juce::AudioParameterBool), which made the
plugin state restoration test fail at level 6. Arbitrary values are
still sent to these parameters at level 8 and above.

Hosted VST3 parameters don't report isBoolean, so two-step parameters
are identified by their number of steps as well.

Author: drowaudio

CHANGELIST.md

@@ -15,6 +15,7 @@
 - `--help` output is now generated by CLI11
 - Added a "Discrete parameter state restoration" test (strictness 8) which checks a discrete parameter has the same value after restoring a state, whatever value it held beforehand. This fails for parameters that keep the raw normalised value from the host instead of mapping it to a step (e.g. `juce::AudioParameterBool`)
 - Fixed false failures in the "Plugin state restoration" test where the first parameter was compared against the last value sent by a previous test rather than the plugin's own value
+- Below strictness level 8, two-step (on/off) parameters are now only sent 0 or 1 when tests randomise parameter values. Arbitrary values are still sent to them at level 8 and above, and to all other parameters at every level
 - Enabled the editor stress and extreme (real-time allocation / oversized block) tests that were present in the source tree but had not been compiled into the build
 
 ### 1.0.5

CLAUDE.md

@@ -405,6 +405,7 @@ static MyNewTest myNewTest;
 
 Located in `TestUtilities.h`:
 - `getNonBypassAutomatableParameters()` - Get automatable params
+- `getRandomParameterValue()` - Random value to set on a param (only 0 or 1 for two-step params below strictness 8)
 - `fillNoise()` - Fill buffer with random audio
 - `countNaNs()`, `countInfs()`, `countSubnormals()` - Audio validation
 - `ScopedEditorShower` - RAII editor creation/destruction

source/TestUtilities.h

@@ -53,6 +53,23 @@ static inline juce::Array<juce::AudioProcessorParameter*> getNonBypassAutomatabl
     return parameters;
 }
 
+/** Returns a random normalised value to set on a parameter.
+
+    Below strictness level 8, two-step (on/off) parameters are only sent 0 or 1.
+    Any value is valid, but some plugins keep the values in between rather than
+    mapping them to a step, which the state restoration tests then pick up.
+*/
+static inline float getRandomParameterValue (juce::Random& r, const juce::AudioProcessorParameter& parameter, int strictnessLevel)
+{
+    // N.B. hosted VST3 parameters don't report isBoolean so also check the number of steps
+    const bool isTwoStep = parameter.isBoolean() || parameter.getNumSteps() == 2;
+
+    if (isTwoStep && strictnessLevel < 8)
+        return r.nextBool() ? 1.0f : 0.0f;
+
+    return r.nextFloat();
+}
+
 //==============================================================================
 template<typename UnaryFunction>
 void iterateAudioBuffer (juce::AudioBuffer<float>& ab, UnaryFunction fn)

source/tests/BasicTests.cpp

@@ -347,7 +347,7 @@ struct PluginStateTest  : public PluginTest
 
         // Set random parameter values
         for (auto parameter : getNonBypassAutomatableParameters (instance))
-            parameter->setValue (r.nextFloat());
+            parameter->setValue (getRandomParameterValue (r, *parameter, ut.getOptions().strictnessLevel));
 
         // Restore original state
         callSetStateInformationOnMessageThreadIfVST3 (instance, originalState);
@@ -388,7 +388,7 @@ struct PluginStateTestRestoration   : public PluginTest
         for (auto parameter : getNonBypassAutomatableParameters(instance))
         {
 			const auto originalValue = parameter->getValue();
-            parameter->setValue(r.nextFloat());
+            parameter->setValue (getRandomParameterValue (r, *parameter, ut.getOptions().strictnessLevel));
 
             // Restore original state
             callSetStateInformationOnMessageThreadIfVST3(instance, originalState);
@@ -539,7 +539,7 @@ struct AutomationTest  : public PluginTest
                         for (int i = 0; i < juce::jmin (10, parameters.size()); ++i)
                         {
                             const int paramIndex = r.nextInt (parameters.size());
-                            parameters[paramIndex]->setValue (r.nextFloat());
+                            parameters[paramIndex]->setValue (getRandomParameterValue (r, *parameters[paramIndex], ut.getOptions().strictnessLevel));
                         }
                     }
 
@@ -617,7 +617,7 @@ struct EditorAutomationTest : public PluginTest
         while (--numBlocks >= 0)
         {
             for (auto parameter : parameters)
-                parameter->setValue (r.nextFloat());
+                parameter->setValue (getRandomParameterValue (r, *parameter, ut.getOptions().strictnessLevel));
 
             ut.resetTimeout();
             juce::Thread::sleep (10);
@@ -767,7 +767,7 @@ struct BackgroundThreadStateTest    : public PluginTest
 
         // Set random parameter values
         for (auto parameter : parameters)
-            parameter->setValue (r.nextFloat());
+            parameter->setValue (getRandomParameterValue (r, *parameter, ut.getOptions().strictnessLevel));
 
         // Restore original state
         callSetStateInformationOnMessageThreadIfVST3 (instance, originalState);
@@ -804,6 +804,7 @@ struct ParameterThreadSafetyTest    : public PluginTest
         auto parameters = getNonBypassAutomatableParameters (instance);
         const bool isPluginInstrument = instance.getPluginDescription().isInstrument;
         const int numBlocks = 500;
+        const int runStrictnessLevel = ut.getOptions().strictnessLevel;
 
         // This emulates the plugin itself setting a value for example from a slider within its UI
         juce::MessageManager::callAsync ([&, threadRandom = r]() mutable
@@ -812,7 +813,7 @@ struct ParameterThreadSafetyTest    : public PluginTest
 
                                        for (int i = 0; i < numBlocks; ++i)
                                            for (auto param : parameters)
-                                               param->setValueNotifyingHost (threadRandom.nextFloat());
+                                               param->setValueNotifyingHost (getRandomParameterValue (threadRandom, *param, runStrictnessLevel));
 
                                        endWaiter.signal();
                                    });
@@ -842,7 +843,7 @@ struct ParameterThreadSafetyTest    : public PluginTest
                 addNoteOff (mb, noteChannel, noteNumber, 0);
 
             for (auto param : parameters)
-                param->setValue (r.nextFloat());
+                param->setValue (getRandomParameterValue (r, *param, runStrictnessLevel));
 
             fillNoise (ab);
 

source/tests/ParameterFuzzTests.cpp

@@ -44,7 +44,7 @@ struct FuzzParametersTest  : public PluginTest
 
         for (int i = 0; i < 5; ++i)
         {
-            const float value = r.nextFloat();
+            const float value = getRandomParameterValue (r, parameter, ut.getOptions().strictnessLevel);
 
             parameter.setValue (value);
             const float v = parameter.getValue();