Re-enable 4 disabled ShuntingLoop exception handling tests (#17)

* Enable previously disabled ShuntingLoop tests and improve Array2DMapTest documentation
* Update CLAUDE.md to reflect re-enabled tests
* Fix test expectation: AssertionError instead of Exception

The test constructor_minimimalContext_throwsException() was expecting
Exception::class but the code throws AssertionError at line 104 when
context.getGraph().size() is 0. Updated test to expect AssertionError
to match actual behavior and align with similar test pattern at line 92.

This follows CLAUDE.md guidance to be conservative with simulation
core changes - the assertion is intentional validation that requires
the -ea flag.
---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: bedaHovorka <bedaHovorka@users.noreply.github.com>

Author: 3 people

CLAUDE.md

@@ -395,7 +395,7 @@ src/
 
 **Key Facts:**
 - **Duration:** ~1 week intensive manual conversion (vs. estimated 3-4 weeks)
-- **Test parity:** 242/242 tests restored and passing (236 pass, 5 skipped @Disabled, 1 property change test)
+- **Test parity:** 242/242 tests restored and passing (240 pass, 1 skipped @Disabled, 1 property change test)
 - **Approach:** Conservative structure-preserving conversion - no unsolicited refactoring
 - **Automated tools:** Attempted Python regex converter - **failed** (enum syntax, inner classes, generics)
 - **Critical lesson:** Legacy codebase migration requires manual conversion with architectural understanding
@@ -1013,11 +1013,10 @@ None. All critical bugs identified by SonarQube have been fixed.
 
 ### Test Suite Notes
 
-**Skipped Tests:** 5 tests (2.1% of suite) are currently disabled:
-- `ShuntingLoopTest`: 4 tests marked with `@Disabled` annotation
-- `XMLContextFactoryTest`: 1 test with conditional skip logic
+**Skipped Tests:** 1 test (0.4% of suite) is currently disabled:
+- `Array2DMapTest.testSpeed()`: Performance benchmark marked with `@Disabled` annotation due to timing variability
 
-These skipped tests document known initialization edge cases and do not indicate failures. See test source files for specific skip reasons.
+**Note:** As of January 2026, 4 previously disabled ShuntingLoop tests were re-enabled after confirming they properly verify exception handling for invalid contexts. The tests validate that ShuntingLoop fails gracefully (throwing appropriate exceptions) when given incompatible network structures, which is correct behavior despite the design limitation documented as SIM-004.
 
 ### Reference Reports
 

src/test/kotlin/cz/vutbr/fit/interlockSim/sim/ShuntingLoopTest.kt

@@ -82,10 +82,6 @@ class ShuntingLoopTest {
 		}
 
 		@Test
-		@Disabled(
-			"BUG-004: ShuntingLoop is tightly coupled to vyhybna.xml structure with hardcoded grid coordinates. " +
-				"Cannot test with arbitrary contexts. Requires refactoring to configuration-based approach."
-		)
 		fun constructor_emptyContext_throwsAssertionError() {
 			val emptyContext = MockSimulationContext()
 
@@ -97,10 +93,6 @@ class ShuntingLoopTest {
 		}
 
 		@Test
-		@Disabled(
-			"BUG-004: ShuntingLoop is tightly coupled to vyhybna.xml structure with hardcoded grid coordinates. " +
-				"Cannot test with arbitrary contexts. Requires refactoring to configuration-based approach."
-		)
 		fun constructor_minimimalContext_throwsException() {
 			// Load minimal network fixture (only 1 InOut, insufficient for ShuntingLoop)
 			val xml =
@@ -115,7 +107,7 @@ class ShuntingLoopTest {
 			assertThatBlock { ShuntingLoop(simContext, 60L) }
 				.withMessage("ShuntingLoop requires specific network structure from vyhybna.xml")
 				.isFailure()
-				.isInstanceOf(Exception::class)
+				.isInstanceOf(AssertionError::class)
 		}
 	}
 
@@ -286,10 +278,6 @@ class ShuntingLoopTest {
 		}
 
 		@Test
-		@Disabled(
-			"BUG-004: ShuntingLoop is tightly coupled to vyhybna.xml structure with hardcoded grid coordinates. " +
-				"Cannot test with arbitrary contexts. Requires refactoring to configuration-based approach."
-		)
 		fun constructor_contextWithoutRequiredElements_throwsException() {
 			// Load linear-track.xml which doesn't have the vyhybna structure
 			val xml =
@@ -308,10 +296,6 @@ class ShuntingLoopTest {
 		}
 
 		@Test
-		@Disabled(
-			"BUG-004: ShuntingLoop is tightly coupled to vyhybna.xml structure with hardcoded grid coordinates. " +
-				"Cannot test with arbitrary contexts. Requires refactoring to configuration-based approach."
-		)
 		fun constructor_switchBasicNetwork_throwsException() {
 			// Load switch-basic.xml which has a switch but not the full vyhybna structure
 			val xml =

src/test/kotlin/cz/vutbr/fit/interlockSim/util/Array2DMapTest.kt

@@ -245,9 +245,20 @@ class Array2DMapTest {
 	}
 
 	/**
-	 * Test method for {@link cz.vutbr.fit.interlockSim.util.Array2DMap}.
+	 * Performance benchmark for {@link cz.vutbr.fit.interlockSim.util.Array2DMap}.
+	 *
+	 * This test is disabled because:
+	 * 1. It's a performance benchmark, not a functional test
+	 * 2. It has inherent timing variability that causes flaky failures
+	 * 3. Historical results show minimal performance difference (see comments below)
+	 *
+	 * Original conclusion: "The speedup is almost none, but at least when calling
+	 * get(Int,Int) directly, the creation of key objects is eliminated."
+	 *
+	 * If you need to run performance benchmarks, consider using JMH (Java Microbenchmark Harness)
+	 * instead of JUnit assertions.
 	 */
-	@Disabled("Performance test that often fails due to timing variability")
+	@Disabled("Performance benchmark with timing variability - not a functional test")
 	@Test
 	fun testSpeed() {
 		@Suppress("UNCHECKED_CAST")
@@ -256,7 +267,7 @@ class Array2DMapTest {
 		@Suppress("UNCHECKED_CAST")
 		val tst2 = tst(treeMap as Map<Point, Int>)
 		// cil: zrychleni operace vyhledani polozky
-		println("$tst1 $tst2")
+		println("Array2DMap: $tst1 ns, TreeMap: $tst2 ns")
 		assertThat(tst1).isLessThan(tst2)
 		// zaver: zrychleni neni skoro zadne
 		// vsak je aspon pri volani primo get(Int,Int) eliminovano vytvareni klicovacich objektu