Add tests for WTC compression

nise-backend/src/test/kotlin/com/nisemoe/nise/osu/WtcTest.kt

@@ -0,0 +1,44 @@
+package com.nisemoe.nise.osu
+
+import com.nisemoe.nise.replays.wtcCompress
+import com.nisemoe.nise.replays.wtcDecompress
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
+import org.junit.jupiter.api.Assertions
+import org.testcontainers.shaded.org.bouncycastle.util.Arrays
+import java.nio.file.Paths
+import kotlin.test.assertEquals
+
+class WtcTest {
+    private val resourcesPath = Paths.get("src", "test", "resources", "wtc")
+
+    /**
+     * Compares the bytes produced from the `wtcCompress()` function with bytes produced from the Python implementation of WTC.
+     */
+    @ParameterizedTest
+    @ValueSource(strings = ["replay_1", "replay_2", "replay_3", "replay_4"])
+    fun wtcCompressReturnsCorrectBytes(replayName: String) {
+        val expected = resourcesPath.resolve("${replayName}_compressed.dat").toFile().readBytes()
+        val replayEvents = resourcesPath.resolve("${replayName}_events.txt").toFile().readText()
+
+        val wtcCompressed = wtcCompress(replayEvents)
+
+        // We include a version header at the start of the compressed byte array - create a new array excluding these
+        // so we can compare just the raw data with the Python WTC implementation's output.
+        // (remove the first two bytes since the version header is a Short)
+        val wtcCompressedWithoutVersionHeader = Arrays.copyOfRange(wtcCompressed, 2, wtcCompressed.size)
+
+        Assertions.assertArrayEquals(expected, wtcCompressedWithoutVersionHeader)
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = ["replay_1", "replay_2", "replay_3", "replay_4"])
+    fun wtcDecompressReturnsCorrectReplayFrames(replayName: String) {
+        val expected = resourcesPath.resolve("${replayName}_decompressed.txt").toFile().readText()
+        val compressedReplay = resourcesPath.resolve("${replayName}_compressed.dat").toFile().readBytes()
+
+        val wtcDecompressed = wtcDecompress(compressedReplay, false)
+
+        assertEquals(expected, wtcDecompressed)
+    }
+}