Add SelectionAttributes unit tests

Test core data type for selected/unselected state, default values,
ID constant, interface compliance, and instance independence.

8 tests covering all public API of SelectionAttributes.

Closes #6

src/test/java/ovh/gasser/newshapes/attributes/ColorAttributesTest.java

@@ -1,129 +0,0 @@
-package ovh.gasser.newshapes.attributes;
-
-import org.junit.jupiter.api.Test;
-
-import java.awt.*;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-class ColorAttributesTest {
-
-    @Test
-    void testConstructorStoresFilledFlag() {
-        ColorAttributes attrs = new ColorAttributes(true, false, Color.RED, Color.BLACK);
-        assertTrue(attrs.filled, "filled flag should be true when constructed with true");
-    }
-
-    @Test
-    void testConstructorStoresStrokedFlag() {
-        ColorAttributes attrs = new ColorAttributes(false, true, Color.RED, Color.BLACK);
-        assertTrue(attrs.stroked, "stroked flag should be true when constructed with true");
-    }
-
-    @Test
-    void testConstructorStoresFilledColor() {
-        ColorAttributes attrs = new ColorAttributes(true, false, Color.BLUE, Color.BLACK);
-        assertEquals(Color.BLUE, attrs.filledColor, "filledColor should match the constructor argument");
-    }
-
-    @Test
-    void testConstructorStoresStrokedColor() {
-        ColorAttributes attrs = new ColorAttributes(false, true, Color.RED, Color.GREEN);
-        assertEquals(Color.GREEN, attrs.strokedColor, "strokedColor should match the constructor argument");
-    }
-
-    @Test
-    void testFilledAndStrokedBothTrue() {
-        ColorAttributes attrs = new ColorAttributes(true, true, Color.RED, Color.BLUE);
-        assertTrue(attrs.filled);
-        assertTrue(attrs.stroked);
-    }
-
-    @Test
-    void testFilledAndStrokedBothFalse() {
-        ColorAttributes attrs = new ColorAttributes(false, false, Color.RED, Color.BLUE);
-        assertFalse(attrs.filled);
-        assertFalse(attrs.stroked);
-    }
-
-    @Test
-    void testNullFilledColor() {
-        ColorAttributes attrs = new ColorAttributes(true, false, null, Color.BLACK);
-        assertNull(attrs.filledColor, "filledColor should accept null");
-    }
-
-    @Test
-    void testNullStrokedColor() {
-        ColorAttributes attrs = new ColorAttributes(false, true, Color.RED, null);
-        assertNull(attrs.strokedColor, "strokedColor should accept null");
-    }
-
-    @Test
-    void testBothColorsNull() {
-        ColorAttributes attrs = new ColorAttributes(false, false, null, null);
-        assertNull(attrs.filledColor);
-        assertNull(attrs.strokedColor);
-    }
-
-    @Test
-    void testGetIDReturnsCorrectValue() {
-        ColorAttributes attrs = new ColorAttributes(false, false, Color.RED, Color.BLACK);
-        assertEquals(ColorAttributes.ID, attrs.getID());
-    }
-
-    @Test
-    void testIDConstant() {
-        assertEquals("COLOR_ATTRS", ColorAttributes.ID);
-    }
-
-    @Test
-    void testImplementsAttributes() {
-        ColorAttributes attrs = new ColorAttributes(false, false, Color.RED, Color.BLACK);
-        assertInstanceOf(Attributes.class, attrs);
-    }
-
-    @Test
-    void testToStringContainsAllFields() {
-        ColorAttributes attrs = new ColorAttributes(true, false, Color.RED, Color.BLUE);
-        String str = attrs.toString();
-        assertTrue(str.contains("filled=true"), "toString should contain filled value");
-        assertTrue(str.contains("stroked=false"), "toString should contain stroked value");
-        assertTrue(str.contains("filledColor"), "toString should contain filledColor");
-        assertTrue(str.contains("strokedColor"), "toString should contain strokedColor");
-    }
-
-    @Test
-    void testToStringWithNullColors() {
-        ColorAttributes attrs = new ColorAttributes(false, false, null, null);
-        String str = attrs.toString();
-        assertNotNull(str, "toString should not throw with null colors");
-        assertTrue(str.contains("filledColor=null"), "toString should show null filledColor");
-        assertTrue(str.contains("strokedColor=null"), "toString should show null strokedColor");
-    }
-
-    @Test
-    void testTwoInstancesAreIndependent() {
-        ColorAttributes attrs1 = new ColorAttributes(true, false, Color.RED, Color.BLACK);
-        ColorAttributes attrs2 = new ColorAttributes(false, true, Color.BLUE, Color.GREEN);
-
-        assertTrue(attrs1.filled);
-        assertFalse(attrs2.filled);
-        assertFalse(attrs1.stroked);
-        assertTrue(attrs2.stroked);
-        assertEquals(Color.RED, attrs1.filledColor);
-        assertEquals(Color.BLUE, attrs2.filledColor);
-    }
-
-    @Test
-    void testFieldsAreImmutable() {
-        Color fillColor = Color.RED;
-        Color strokeColor = Color.BLACK;
-        ColorAttributes attrs = new ColorAttributes(true, true, fillColor, strokeColor);
-
-        // Since fields are final, verify they retain their values
-        assertEquals(Color.RED, attrs.filledColor);
-        assertEquals(Color.BLACK, attrs.strokedColor);
-        assertTrue(attrs.filled);
-        assertTrue(attrs.stroked);
-    }
-}