fix(nvenc): dynamic nv codec sdk selection (#5451)

tests/unit/test_nvenc_version.cpp

@@ -0,0 +1,52 @@
+/**
+ * @file tests/unit/test_nvenc_version.cpp
+ * @brief Tests for runtime NVENC SDK version selection.
+ */
+
+// standard includes
+#include <array>
+#include <cstdint>
+
+// lib includes
+#include <gtest/gtest.h>
+
+// local includes
+#include "src/nvenc/nvenc_version.h"
+
+namespace {
+
+  /**
+   * @brief Expected SDK selection for a driver API version.
+   */
+  struct nvenc_version_test_case {
+    std::uint32_t max_version;  ///< Maximum API version reported by the driver.
+    nvenc::nvenc_sdk_version expected;  ///< SDK implementation Sunshine should select.
+  };
+
+  TEST(NvencVersionTest, DecodesPackedDriverVersion) {
+    EXPECT_EQ(nvenc::decode_nvenc_driver_version((11U << 4U) | 0U), 1100U);
+    EXPECT_EQ(nvenc::decode_nvenc_driver_version((13U << 4U) | 1U), 1301U);
+  }
+
+  TEST(NvencVersionTest, SelectsNewestCompatibleSdk) {
+    using enum nvenc::nvenc_sdk_version;
+    constexpr std::array test_cases {
+      nvenc_version_test_case {1000U, unsupported},
+      nvenc_version_test_case {1099U, unsupported},
+      nvenc_version_test_case {1100U, sdk_11_0},
+      nvenc_version_test_case {1101U, sdk_11_0},
+      nvenc_version_test_case {1199U, sdk_11_0},
+      nvenc_version_test_case {1200U, sdk_12_0},
+      nvenc_version_test_case {1201U, sdk_12_0},
+      nvenc_version_test_case {1299U, sdk_12_0},
+      nvenc_version_test_case {1300U, sdk_13_0},
+      nvenc_version_test_case {1301U, sdk_13_0},
+      nvenc_version_test_case {1400U, sdk_13_0},
+    };
+
+    for (const auto &[max_version, expected] : test_cases) {
+      EXPECT_EQ(nvenc::select_nvenc_sdk_version(max_version), expected);
+    }
+  }
+
+}  // namespace