test: add edge case tests for shapes

Add 19 tests covering edge cases across all shape types:
- Negative coordinates: SRectangle, SCircle, STriangle, translate
- Zero dimensions: zero width/height rectangle, zero radius circle
- Resize clamping: verify width/height minimum enforcement
- Null handling: null/blank text normalization, unknown attribute key, empty collection
- Large values: Integer.MAX_VALUE/2 coords, MAX/MIN_VALUE translate

Closes #13

src/test/java/ovh/gasser/newshapes/shapes/EdgeCaseTest.java

@@ -0,0 +1,223 @@
+package ovh.gasser.newshapes.shapes;
+
+import ovh.gasser.newshapes.App;
+import ovh.gasser.newshapes.attributes.SelectionAttributes;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import java.awt.*;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class EdgeCaseTest {
+
+    // -------------------------------------------------------------------------
+    // NegativeCoordinates
+    // -------------------------------------------------------------------------
+
+    @Nested
+    class NegativeCoordinates {
+
+        @Test
+        void rectangleAtNegativeCoordsShouldPreserveBounds() {
+            SRectangle rect = SRectangle.create(-10, -20, 50, 50);
+            Rectangle bounds = rect.getBounds();
+            assertEquals(-10, bounds.x,      "x should be -10");
+            assertEquals(-20, bounds.y,      "y should be -20");
+            assertEquals(50,  bounds.width,  "width should be 50");
+            assertEquals(50,  bounds.height, "height should be 50");
+        }
+
+        @Test
+        void circleAtNegativeCoordsShouldPreserveBounds() {
+            SCircle circle = SCircle.create(-30, -40, 25);
+            Rectangle bounds = circle.getBounds();
+            assertEquals(-30, bounds.x,      "x should be -30");
+            assertEquals(-40, bounds.y,      "y should be -40");
+            assertEquals(50,  bounds.width,  "width should be radius*2 = 50");
+            assertEquals(50,  bounds.height, "height should be radius*2 = 50");
+        }
+
+        @Test
+        void triangleAtNegativeCoordsShouldPreserveBounds() {
+            STriangle tri = STriangle.create(-5, -15, 60, Color.RED, Color.BLACK);
+            Rectangle bounds = tri.getBounds();
+            assertEquals(-5,  bounds.x,      "x should be -5");
+            assertEquals(-15, bounds.y,      "y should be -15");
+            assertEquals(60,  bounds.width,  "width should be 60");
+            assertEquals(60,  bounds.height, "height should be 60");
+        }
+
+        @Test
+        void translateToNegativePositionShouldUpdateBoundsCorrectly() {
+            SRectangle rect = SRectangle.create(10, 20, 80, 40);
+            rect.translate(-50, -70);
+            Rectangle bounds = rect.getBounds();
+            assertEquals(-40, bounds.x, "x after translate should be -40");
+            assertEquals(-50, bounds.y, "y after translate should be -50");
+            // dimensions must be unchanged
+            assertEquals(80, bounds.width,  "width must remain 80 after translate");
+            assertEquals(40, bounds.height, "height must remain 40 after translate");
+        }
+    }
+
+    // -------------------------------------------------------------------------
+    // ZeroDimensions
+    // -------------------------------------------------------------------------
+
+    @Nested
+    class ZeroDimensions {
+
+        @Test
+        void rectangleWithZeroWidthShouldReturnZeroWidthFromFactory() {
+            SRectangle rect = SRectangle.create(0, 0, 0, 50);
+            assertEquals(0, rect.getBounds().width,
+                    "factory should allow zero width without clamping");
+        }
+
+        @Test
+        void rectangleWithZeroHeightShouldReturnZeroHeightFromFactory() {
+            SRectangle rect = SRectangle.create(0, 0, 50, 0);
+            assertEquals(0, rect.getBounds().height,
+                    "factory should allow zero height without clamping");
+        }
+
+        @Test
+        void circleWithZeroRadiusShouldHaveZeroBoundsDimensions() {
+            SCircle circle = SCircle.create(5, 10, 0);
+            assertEquals(0, circle.getRadius(),        "radius should be 0");
+            assertEquals(0, circle.getBounds().width,  "bounds width should be 0 (radius*2)");
+            assertEquals(0, circle.getBounds().height, "bounds height should be 0 (radius*2)");
+        }
+    }
+
+    // -------------------------------------------------------------------------
+    // ResizeClamping
+    // -------------------------------------------------------------------------
+
+    @Nested
+    class ResizeClamping {
+
+        @Test
+        void rectangleResizedToNegativeShouldClampWidthToOne() {
+            // Start with a 10x10 rect and drag the E handle far to the left
+            SRectangle rect = SRectangle.create(0, 0, 10, 10);
+            rect.resize(ResizeHandle.E, -200, 0);
+            assertTrue(rect.getBounds().width >= 1,
+                    "width must be clamped to a minimum of 1 after negative resize");
+            assertEquals(1, rect.getBounds().width,
+                    "width should be exactly 1 after extreme negative resize on E handle");
+        }
+
+        @Test
+        void rectangleResizedToNegativeShouldClampHeightToOne() {
+            SRectangle rect = SRectangle.create(0, 0, 10, 10);
+            rect.resize(ResizeHandle.S, 0, -200);
+            assertTrue(rect.getBounds().height >= 1,
+                    "height must be clamped to a minimum of 1 after negative resize");
+            assertEquals(1, rect.getBounds().height,
+                    "height should be exactly 1 after extreme negative resize on S handle");
+        }
+
+        @Test
+        void circleResizedToNegativeShouldClampToTwo() {
+            SCircle circle = SCircle.create(0, 0, 50);
+            // Drag E handle far to the left → shrink
+            circle.resize(ResizeHandle.E, -500, 0);
+            assertTrue(circle.getBounds().width >= 2,
+                    "circle width must be clamped to a minimum of 2");
+            assertTrue(circle.getBounds().height >= 2,
+                    "circle height must be clamped to a minimum of 2");
+            assertEquals(2, circle.getBounds().width,
+                    "circle width should be exactly 2 after extreme negative resize");
+            assertEquals(2, circle.getBounds().height,
+                    "circle height should be exactly 2 after extreme negative resize");
+        }
+    }
+
+    // -------------------------------------------------------------------------
+    // NullHandling
+    // -------------------------------------------------------------------------
+
+    @Nested
+    class NullHandling {
+
+        @Test
+        void textCreatedWithNullShouldReturnPlaceholder() {
+            SText text = SText.create(0, 0, null);
+            assertEquals(SText.PLACEHOLDER_TEXT, text.getText(),
+                    "null input should be normalized to the placeholder text");
+        }
+
+        @Test
+        void textCreatedWithBlankStringShouldReturnPlaceholder() {
+            SText text = SText.create(0, 0, "   ");
+            assertEquals(SText.PLACEHOLDER_TEXT, text.getText(),
+                    "blank string input should be normalized to the placeholder text");
+        }
+
+        @Test
+        void getAttributesWithUnknownKeyShouldReturnNull() {
+            SRectangle rect = SRectangle.create(0, 0, 50, 50);
+            assertNull(rect.getAttributes("NONEXISTENT"),
+                    "getAttributes() with an unknown key must return null");
+        }
+
+        @Test
+        void emptyCollectionCreationShouldNotThrow() {
+            assertDoesNotThrow(() -> SCollection.of(),
+                    "SCollection.of() with no arguments must not throw");
+        }
+
+        @Test
+        void emptyCollectionGetBoundsShouldReturnWindowSize() {
+            SCollection collection = SCollection.of();
+            Rectangle bounds = collection.getBounds();
+            assertNotNull(bounds, "getBounds() on empty collection must not return null");
+            assertEquals(App.WIN_SIZE.width,  bounds.width,
+                    "empty collection bounds width should equal WIN_SIZE.width");
+            assertEquals(App.WIN_SIZE.height, bounds.height,
+                    "empty collection bounds height should equal WIN_SIZE.height");
+        }
+    }
+
+    // -------------------------------------------------------------------------
+    // LargeValues
+    // -------------------------------------------------------------------------
+
+    @Nested
+    class LargeValues {
+
+        @Test
+        void rectangleAtMaxIntHalfCoordsShouldNotThrow() {
+            int halfMax = Integer.MAX_VALUE / 2;
+            assertDoesNotThrow(() -> SRectangle.create(halfMax, halfMax, 100, 100),
+                    "SRectangle.create() with very large coordinates must not throw");
+        }
+
+        @Test
+        void rectangleAtMaxIntHalfCoordsPreservesBounds() {
+            int halfMax = Integer.MAX_VALUE / 2;
+            SRectangle rect = SRectangle.create(halfMax, halfMax, 100, 100);
+            assertEquals(halfMax, rect.getBounds().x,   "x should be Integer.MAX_VALUE/2");
+            assertEquals(halfMax, rect.getBounds().y,   "y should be Integer.MAX_VALUE/2");
+            assertEquals(100,     rect.getBounds().width,  "width should be 100");
+            assertEquals(100,     rect.getBounds().height, "height should be 100");
+        }
+
+        @Test
+        void translateWithLargeValuesShouldNotThrow() {
+            SRectangle rect = SRectangle.create(0, 0, 50, 50);
+            // Integer overflow is a known platform behaviour; we only assert no exception
+            assertDoesNotThrow(() -> rect.translate(Integer.MAX_VALUE, Integer.MAX_VALUE),
+                    "translate() with Integer.MAX_VALUE must not throw (overflow is acceptable)");
+        }
+
+        @Test
+        void translateWithLargeNegativeValuesShouldNotThrow() {
+            SRectangle rect = SRectangle.create(0, 0, 50, 50);
+            assertDoesNotThrow(() -> rect.translate(Integer.MIN_VALUE, Integer.MIN_VALUE),
+                    "translate() with Integer.MIN_VALUE must not throw (overflow is acceptable)");
+        }
+    }
+}