Add tests for EnvelopeADSR

CMakeLists.txt

@@ -61,6 +61,7 @@ if(NOT CMAKE_CROSSCOMPILING)
             "lib/grit/audio/dynamic/gain_computer_test.cpp"
             "lib/grit/audio/dynamic/transient_shaper_test.cpp"
 
+            "lib/grit/audio/envelope/envelope_adsr_test.cpp"
             "lib/grit/audio/envelope/envelope_follower_test.cpp"
 
             "lib/grit/audio/filter/biquad_test.cpp"

lib/grit/audio/envelope/envelope_adsr_test.cpp

@@ -0,0 +1,45 @@
+#include "envelope_adsr.hpp"
+
+#include <catch2/catch_template_test_macros.hpp>
+#include <catch2/generators/catch_generators.hpp>
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+
+TEMPLATE_TEST_CASE("audio/envelope: EnvelopeADSR", "", float, double)
+{
+    using Float = TestType;
+
+    // TODO: Check why the error with float32 is so high
+    static constexpr auto tolerance = sizeof(Float) == 4 ? 1e-2 : 1e-6;
+
+    auto const advance = [](auto& env, auto count) {
+        for (auto i{0}; i < count - 1; ++i) {
+            [[maybe_unused]] auto out = env();
+        }
+        return env();
+    };
+
+    auto const attack  = GENERATE(2000, 44'100, 96'000);
+    auto const sustain = GENERATE(Float(0.75), Float(0.9));
+
+    auto const decay   = attack / 4;
+    auto const release = attack / 2;
+
+    auto adsr = grit::EnvelopeADSR<Float>{};
+    adsr.setAttack(Float(attack));
+    adsr.setDecay(Float(decay));
+    adsr.setSustain(sustain);
+    adsr.setRelease(Float(release));
+
+    for (auto i{0}; i < 100; ++i) {
+        CAPTURE(i);
+        REQUIRE_THAT(adsr(), Catch::Matchers::WithinAbs(Float(0), tolerance));
+    }
+
+    adsr.gate(true);
+    REQUIRE_THAT(advance(adsr, attack), Catch::Matchers::WithinAbs(Float(1), tolerance));    // attack
+    REQUIRE_THAT(advance(adsr, decay), Catch::Matchers::WithinAbs(sustain, tolerance));      // decay -> sustain
+    REQUIRE_THAT(advance(adsr, decay * 2), Catch::Matchers::WithinAbs(sustain, tolerance));  // sustain
+
+    adsr.gate(false);
+    REQUIRE_THAT(advance(adsr, release), Catch::Matchers::WithinAbs(Float(0), tolerance));  // release
+}