Add unit tests for UI layouts package

[shai-almog]

Created extensive unit tests for the following layout classes:

• BorderLayoutTest: Tests for all constraints (NORTH, SOUTH, EAST, WEST, CENTER, OVERLAY), center behaviors, landscape swap, scale edges, and factory methods
• BoxLayoutTest: Tests for X_AXIS, Y_AXIS, X_AXIS_NO_GROW, Y_AXIS_BOTTOM_LAST, alignment options, and all factory methods
• FlowLayoutTest: Tests for horizontal/vertical alignment, fill rows, valign by row, and all enclose factory methods
• GridLayoutTest: Tests for row/column configuration, auto-fit, fill last row, hide zero sized, and landscape mode
• LayeredLayoutTest: Tests for component layering, preferred size in MM, and overlap behavior
• CoordinateLayoutTest: Tests for absolute positioning, scaling, and coordinate transformation

All tests follow existing conventions:

• Extend UITestBase for Display initialization
• Use JUnit 5 annotations and assertions
• Avoid Mockito (use TestCodenameOneImplementation instead)
• Test both API and layout behavior
• Aim for high code coverage

Tests cover constructors, getters/setters, factory methods, layout calculations, preferred size calculations, edge cases, and equals/toString methods for each layout class.

[github-actions]

✅ Continuous Quality Report

Test & Coverage

• ✅ Tests: 865 total, 0 failed, 0 skipped
• 📊 Line coverage: 19.04% [HTML preview] [Download]
  • Lowest covered classes
    • com.codename1.io.services.RSSService$1 – 0.00%
    • com.codename1.io.services.ImageDownloadService – 0.00%
    • com.codename1.io.services.ImageDownloadService$6 – 0.00%
    • com.codename1.io.services.ImageDownloadService$1 – 0.00%
    • com.codename1.io.services.ImageDownloadService$3 – 0.00%
    • com.codename1.io.services.ImageDownloadService$2 – 0.00%
    • com.codename1.io.services.ImageDownloadService$5 – 0.00%
    • com.codename1.io.services.ImageDownloadService$4 – 0.00%
    • com.codename1.io.services.TwitterRESTService$1 – 0.00%
    • com.codename1.io.services.RSSService$1FinishParsing – 0.00%

Static Analysis

• ❌ SpotBugs: 993 findings (High: 92, Normal: 484, Low: 417) [HTML preview] [Download]
  • Top findings
    • High: CodenameOne/src/com/codename1/charts/util/ColorUtil.java:38 – Field isn't final but should be (rule: MS_SHOULD_BE_FINAL)
    • High: CodenameOne/src/com/codename1/charts/util/ColorUtil.java:30 – Field isn't final but should be (rule: MS_SHOULD_BE_FINAL)
    • High: CodenameOne/src/com/codename1/charts/util/ColorUtil.java:33 – Field isn't final but should be (rule: MS_SHOULD_BE_FINAL)
    • High: CodenameOne/src/com/codename1/charts/views/XYChart.java:128 – Call to equals() comparing different types (rule: EC_UNRELATED_TYPES)
    • High: CodenameOne/src/com/codename1/compat/java/util/Objects.java:51 – Redundant nullcheck of value known to be non-null (rule: RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE)
    • …and 988 more
• ❌ PMD: 2726 findings (P2: 1, P3: 649, P4: 2076) [HTML preview] [Download]
  • Top findings
    • P2: CodenameOne/src/com/codename1/ui/Display.java:1012 – Avoid using a branching statement as the last in a loop. (rule: AvoidBranchingStatementAsLastInLoop)
    • P3: CodenameOne/src/com/codename1/facebook/FacebookRESTService.java:76 – Avoid unused constructor parameters such as 'token'. (rule: UnusedFormalParameter)
    • P3: CodenameOne/src/com/codename1/impl/CodenameOneImplementation.java:8380 – These nested if statements could be combined (rule: CollapsibleIfStatements)
    • P3: CodenameOne/src/com/codename1/impl/FullScreenAdService.java:103 – These nested if statements could be combined (rule: CollapsibleIfStatements)
    • P3: CodenameOne/src/com/codename1/io/CSVParser.java:134 – These nested if statements could be combined (rule: CollapsibleIfStatements)
    • …and 2721 more
• ❌ Checkstyle: 192678 findings (Warning: 192678) [HTML preview] [Download]
  • Top findings
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:30:1 – Extra separation in import group before 'java.io.IOException' (rule: CustomImportOrderCheck)
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:32 – First sentence of Javadoc is missing an ending period. (rule: SummaryJavadocCheck)
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:36 – Line is longer than 100 characters (found 143). (rule: LineLengthCheck)
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:39:5 – 'member def modifier' has incorrect indentation level 4, expected level should be 2. (rule: IndentationCheck)
    • Warning: CodenameOne/src/com/codename1/db/ThreadSafeDatabase.java:40:5 – 'member def modifier' has incorrect indentation level 4, expected level should be 2. (rule: IndentationCheck)
    • …and 192673 more

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