Add comprehensive Shape class tests

Author: skainet-dev

core/src/commonTest/kotlin/sk/ai/net/ShapeTest.kt

@@ -2,12 +2,43 @@ package sk.ai.net
 
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertContentEquals
 
 class ShapeTest {
 
     @Test
-    fun `test scalar`() {
-        val shape = Shape(0)
-        assertEquals(shape, Shape(1, 2))
+    fun volumeIsProductOfDimensions() {
+        val shape = Shape(2, 3, 4)
+        assertEquals(24, shape.volume)
     }
-}
+
+    @Test
+    fun rankIsNumberOfDimensions() {
+        val shape = Shape(2, 3)
+        assertEquals(2, shape.rank)
+    }
+
+    @Test
+    fun equalityChecksAllDimensions() {
+        val shape1 = Shape(2, 3)
+        val shape2 = Shape(2, 3)
+        val shape3 = Shape(3, 2)
+        assertEquals(shape1, shape2)
+        assertFalse(shape1 == shape3)
+    }
+
+    @Test
+    fun constructorCopiesDimensions() {
+        val dims = intArrayOf(2, 3)
+        val shape = Shape(*dims)
+        dims[0] = 5
+        assertContentEquals(intArrayOf(2, 3), shape.dimensions)
+    }
+
+    @Test
+    fun toStringContainsSizeInformation() {
+        val shape = Shape(2, 3)
+        assertEquals("Shape: Dimensions = [2 x 3], Size (Volume) = 6", shape.toString())
+    }
+}