Add layout coverage tests for ui layouts package (#4153)

* Add layout coverage tests for ui layouts package

* Fix layout coverage test compilation issues

* Fix LayeredLayout getter assertions in coverage test

* Adjust TextModeLayout coverage test to avoid null constraints

* Fix TextModeLayout test theme constant

* Adjust TextModeLayout clone assertion

Author: shai-almog

maven/core-unittests/src/test/java/com/codename1/ui/layouts/LayoutsCoverageTest.java

@@ -0,0 +1,187 @@
+package com.codename1.ui.layouts;
+
+import com.codename1.junit.FormTest;
+import com.codename1.junit.UITestBase;
+import com.codename1.testing.TestCodenameOneImplementation;
+import com.codename1.ui.Button;
+import com.codename1.ui.Component;
+import com.codename1.ui.Container;
+import com.codename1.ui.Form;
+import com.codename1.ui.Label;
+import com.codename1.ui.TextComponent;
+import com.codename1.ui.geom.Dimension;
+import com.codename1.ui.table.TableLayout;
+import com.codename1.ui.plaf.UIManager;
+import java.util.Hashtable;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class LayoutsCoverageTest extends UITestBase {
+
+    @FormTest
+    void groupLayoutAutoPaddingAndLinking() {
+        Form form = new Form();
+        Container content = form.getContentPane();
+        GroupLayout layout = new GroupLayout(content);
+        layout.setAutocreateGaps(true);
+        layout.setAutocreateContainerGaps(true);
+        content.setLayout(layout);
+
+        Label first = new Label("First");
+        first.setPreferredSize(new Dimension(20, 10));
+        Button second = new Button("Second");
+        second.setPreferredSize(new Dimension(60, 10));
+        Label third = new Label("Third");
+        third.setPreferredSize(new Dimension(25, 10));
+
+        layout.setHorizontalGroup(
+                layout.createSequentialGroup()
+                        .add(first)
+                        .add(second)
+                        .add(layout.createParallelGroup(GroupLayout.LEADING)
+                                .add(third))
+        );
+
+        layout.setVerticalGroup(
+                layout.createParallelGroup(GroupLayout.BASELINE)
+                        .add(first)
+                        .add(second)
+                        .add(third)
+        );
+
+        layout.linkSize(new Component[]{first, second}, GroupLayout.HORIZONTAL);
+        form.show();
+        TestCodenameOneImplementation.getInstance().dispatchPointerPressAndRelease(1, 1);
+
+        assertTrue(layout.getAutocreateContainerGaps());
+        assertTrue(layout.getAutocreateGaps());
+        assertEquals(first.getWidth(), second.getWidth());
+        assertEquals(third.getHeight(), second.getHeight());
+        assertEquals(layout.getComponentConstraint(first), layout.getComponentConstraint(first));
+    }
+
+    @FormTest
+    void gridBagLayoutStoresConstraintsAndLayouts() {
+        Form form = new Form(new GridBagLayout());
+        GridBagLayout layout = (GridBagLayout) form.getLayout();
+
+        GridBagConstraints leftConstraints = new GridBagConstraints();
+        leftConstraints.gridx = 0;
+        leftConstraints.gridy = 0;
+        leftConstraints.insets = new Insets(1, 2, 3, 4);
+
+        Label left = new Label("L");
+        form.add(leftConstraints, left);
+
+        GridBagConstraints rightConstraints = new GridBagConstraints(1, 0, 1, 1, 1, 0, GridBagConstraints.EAST,
+                GridBagConstraints.HORIZONTAL, new Insets(0, 0, 0, 0), 0, 0);
+        Button right = new Button("R");
+        form.add(rightConstraints, right);
+
+        form.show();
+        TestCodenameOneImplementation.getInstance().dispatchPointerPressAndRelease(2, 2);
+
+        GridBagConstraints stored = (GridBagConstraints) layout.getComponentConstraint(left);
+        assertNotSame(leftConstraints, stored);
+        assertEquals(2, stored.insets.left);
+        assertEquals(GridBagConstraints.HORIZONTAL, ((GridBagConstraints) layout.getComponentConstraint(right)).fill);
+
+        layout.removeLayoutComponent(right);
+        assertEquals(leftConstraints.gridx, ((GridBagConstraints) layout.getComponentConstraint(left)).gridx);
+    }
+
+    @FormTest
+    void gridBagConstraintsValidationAndInsetsEquality() {
+        GridBagConstraints invalid = new GridBagConstraints();
+        invalid.anchor = 99;
+        assertThrows(IllegalArgumentException.class, invalid::verify);
+
+        Insets a = new Insets(1, 2, 3, 4);
+        Insets b = (Insets) a.clone();
+        assertEquals(a, b);
+        assertEquals(a.hashCode(), b.hashCode());
+
+        Insets c = new Insets(0, 0, 0, 0);
+        c.set(5, 6, 7, 8);
+        assertEquals("com.codename1.ui.layouts.Insets[left=6,top=5,right=8,bottom=7]", c.toString());
+    }
+
+    @FormTest
+    void layoutStylePreferredAndContainerGaps() {
+        LayoutStyle shared = LayoutStyle.getSharedInstance();
+        LayoutStyle.setSharedInstance(shared);
+
+        Label before = new Label("Before");
+        Label after = new Label("After");
+        Container parent = new Container();
+
+        int related = shared.getPreferredGap(before, after, LayoutStyle.RELATED, GroupLayout.SOUTH, parent);
+        int unrelated = shared.getPreferredGap(before, after, LayoutStyle.UNRELATED, GroupLayout.EAST, parent);
+        assertTrue(unrelated >= related);
+
+        assertThrows(IllegalArgumentException.class, () -> shared.getPreferredGap(before, after, 99, GroupLayout.NORTH, parent));
+        assertThrows(IllegalArgumentException.class, () -> shared.getPreferredGap(before, null, LayoutStyle.RELATED, GroupLayout.NORTH, parent));
+
+        int containerGap = shared.getContainerGap(before, GroupLayout.SOUTH, parent);
+        assertTrue(containerGap > 0);
+    }
+
+    @FormTest
+    void textModeLayoutGroupsInputsAndClonesConstraints() {
+        Hashtable theme = new Hashtable();
+        theme.put("@textComponentOnTopBool", "true");
+        UIManager.getInstance().setThemeProps(theme);
+        TextModeLayout textLayout = new TextModeLayout(2, 1);
+        Container container = new Container(textLayout);
+
+        TextComponent first = new TextComponent().label("First");
+        first.onTopMode(true);
+        TextComponent second = new TextComponent().label("Second");
+        second.onTopMode(true);
+
+        container.add(textLayout.createConstraint(), first);
+        TableLayout.Constraint constraint = textLayout.createConstraint();
+        constraint.setVerticalSpan(2);
+        container.add(constraint, second);
+
+        Form form = new Form(new BorderLayout());
+        form.add(BorderLayout.CENTER, container);
+        form.show();
+        TestCodenameOneImplementation.getInstance().dispatchPointerPressAndRelease(5, 5);
+
+        TableLayout.Constraint cloned = (TableLayout.Constraint) textLayout.cloneConstraint(constraint);
+        assertEquals(constraint.getVerticalSpan(), cloned.getVerticalSpan());
+        assertEquals(2, ((TableLayout.Constraint) textLayout.table.getComponentConstraint(second)).getVerticalSpan());
+        assertSame(constraint, cloned);
+    }
+
+    @FormTest
+    void layeredLayoutInsetsAndReferenceComponents() {
+        Container container = new Container(new LayeredLayout());
+        LayeredLayout layeredLayout = (LayeredLayout) container.getLayout();
+
+        Button base = new Button("Base");
+        Button overlay = new Button("Overlay");
+        container.add(base);
+        container.add(overlay);
+
+        layeredLayout.setInsets(base, "1px 2px auto auto");
+        layeredLayout.setInsets(overlay, "auto auto auto auto");
+        layeredLayout.setReferenceComponentLeft(overlay, base, 1f);
+        layeredLayout.setReferenceComponentTop(overlay, base, 0f);
+
+        Form form = new Form(new BorderLayout());
+        form.add(BorderLayout.CENTER, container);
+        form.show();
+        TestCodenameOneImplementation.getInstance().dispatchPointerPressAndRelease(10, 10);
+
+        LayeredLayout.LayeredLayoutConstraint baseConstraint = layeredLayout.getLayeredLayoutConstraint(base);
+        assertEquals(LayeredLayout.UNIT_PIXELS, baseConstraint.top().getUnit());
+        assertEquals("2px", baseConstraint.right().getValueAsString());
+
+        LayeredLayout.LayeredLayoutConstraint overlayConstraint = layeredLayout.getLayeredLayoutConstraint(overlay);
+        assertSame(base, overlayConstraint.left().getReferenceComponent());
+        assertEquals(1f, overlayConstraint.left().getReferencePosition());
+        assertEquals(0f, overlayConstraint.top().getReferencePosition());
+    }
+}