test: pin OnnxEvaluator fallback contract

src/test/java/com/fortemate/dicechess/bot/OnnxEvaluatorFallbackTest.java

@@ -0,0 +1,57 @@
+package com.fortemate.dicechess.bot;
+
+import dicechess.engine.jvmapi.JvmApi;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class OnnxEvaluatorFallbackTest {
+
+    @Test
+    void testFallbackForInvalidOrMissingPaths() {
+        var invalidPaths = List.of("", "   ", "no/such/model.onnx");
+        for (var path : invalidPaths) {
+            assertDoesNotThrow(() -> {
+                try (var evaluator = new OnnxEvaluator(path)) {
+                    assertFalse(evaluator.isLoaded(), "isLoaded() should be false for path: " + path);
+                }
+            });
+        }
+
+        assertDoesNotThrow(() -> {
+            try (var evaluator = new OnnxEvaluator(null)) {
+                assertFalse(evaluator.isLoaded(), "isLoaded() should be false for null path");
+            }
+        });
+    }
+
+    @Test
+    void testFallbackForNonOnnxFile(@TempDir Path tempDir) throws IOException {
+        var invalidModelFile = tempDir.resolve("invalid_model.onnx");
+        Files.writeString(invalidModelFile, "this is not a valid onnx model file");
+
+        assertDoesNotThrow(() -> {
+            try (var evaluator = new OnnxEvaluator(invalidModelFile.toString())) {
+                assertFalse(evaluator.isLoaded(), "isLoaded() should be false for non-ONNX file");
+            }
+        });
+    }
+
+    @Test
+    void testEvaluateMatchesEngineHeuristicFallback() {
+        var dfen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 p";
+        var state = JvmApi.parseDfen(dfen);
+
+        try (var evaluator = new OnnxEvaluator(null)) {
+            assertFalse(evaluator.isLoaded());
+            assertEquals(JvmApi.evaluate(state, 0), evaluator.evaluate(state, 0), "White evaluation should match JvmApi.evaluate");
+            assertEquals(JvmApi.evaluate(state, 1), evaluator.evaluate(state, 1), "Black evaluation should match JvmApi.evaluate");
+        }
+    }
+}