tests: add NSSegmentedCell tests

ChangeLog

@@ -1,5 +1,11 @@
 2026-07-12 Todd White <todd.white@thalion.global>
 
+	* Tests/gui/NSSegmentedCell/model.m:
+	* Tests/gui/NSSegmentedCell/TestInfo:
+	Add tests for the NSSegmentedCell model: the defaults, the segment
+	count, the per-segment label, width, enabled, tag and tool tip
+	accessors, the single-selection tracking, selection by tag, and the
+	segment style.
 	* Source/NSScroller.m (-[NSScroller setFloatValue:knobProportion:]):
 	Clamp the value into [0,1] before the redisplay marker is set, so a
 	value of -1 (which matched the marker and was skipped by setDoubleValue:)

Tests/gui/NSSegmentedCell/model.m

@@ -0,0 +1,91 @@
+/* Coverage for the NSSegmentedCell model: the defaults, the segment count,
+   the per-segment label, width, enabled, tag and tool tip accessors, the
+   single-selection tracking (selecting a segment moves the selection), the
+   selection by tag, and the segment style.  The cell touches the font
+   backend, so the set is skipped when the backend is unavailable.
+*/
+#include "Testing.h"
+
+#include <math.h>
+#include <Foundation/NSAutoreleasePool.h>
+
+#include <AppKit/NSApplication.h>
+#include <AppKit/NSSegmentedCell.h>
+
+int
+main(int argc, char **argv)
+{
+  CREATE_AUTORELEASE_POOL(arp);
+  NSSegmentedCell *cell;
+
+  START_SET("NSSegmentedCell model")
+
+  NS_DURING
+  {
+    [NSApplication sharedApplication];
+  }
+  NS_HANDLER
+  {
+    if ([[localException name] isEqualToString: NSInternalInconsistencyException])
+      SKIP("It looks like GNUstep backend is not yet installed")
+  }
+  NS_ENDHANDLER
+
+  cell = AUTORELEASE([[NSSegmentedCell alloc] init]);
+
+  /* Defaults. */
+  pass([cell segmentCount] == 0, "a new cell has no segments");
+  pass([cell selectedSegment] == -1, "a new cell has no selection");
+  pass([cell trackingMode] == NSSegmentSwitchTrackingSelectOne,
+       "the default tracking mode selects one segment");
+
+  /* Segment count and per-segment defaults. */
+  [cell setSegmentCount: 3];
+  pass([cell segmentCount] == 3, "setSegmentCount: sets the number of segments");
+  pass([cell labelForSegment: 0] == nil, "a new segment has no label");
+  pass([cell widthForSegment: 0] == 0.0, "a new segment has zero width");
+  pass([cell isEnabledForSegment: 0] == YES, "a new segment is enabled");
+  pass([cell tagForSegment: 0] == 0, "a new segment has a zero tag");
+  pass([cell isSelectedForSegment: 0] == NO, "a new segment is not selected");
+
+  /* Per-segment accessors round-trip. */
+  [cell setLabel: @"One" forSegment: 0];
+  [cell setLabel: @"Two" forSegment: 1];
+  [cell setLabel: @"Three" forSegment: 2];
+  [cell setWidth: 40.0 forSegment: 1];
+  [cell setTag: 77 forSegment: 2];
+  [cell setToolTip: @"tip" forSegment: 0];
+  pass([[cell labelForSegment: 1] isEqualToString: @"Two"], "the label round trips");
+  pass([cell widthForSegment: 1] == 40.0, "the width round trips");
+  pass([cell tagForSegment: 2] == 77, "the tag round trips");
+  pass([[cell toolTipForSegment: 0] isEqualToString: @"tip"], "the tool tip round trips");
+
+  /* Single-selection tracking: selecting a segment moves the selection. */
+  [cell setSelectedSegment: 1];
+  pass([cell selectedSegment] == 1 && [cell isSelectedForSegment: 1] == YES,
+    "setSelectedSegment: selects the segment");
+  [cell setSelectedSegment: 2];
+  pass([cell selectedSegment] == 2 && [cell isSelectedForSegment: 2] == YES
+    && [cell isSelectedForSegment: 1] == NO,
+    "selecting another segment deselects the previous one");
+  [cell setSelected: NO forSegment: 2];
+  pass([cell isSelectedForSegment: 2] == NO, "setSelected: NO deselects the segment");
+
+  /* Selection by tag. */
+  [cell selectSegmentWithTag: 77];
+  pass([cell selectedSegment] == 2, "selectSegmentWithTag: selects the tagged segment");
+
+  /* Shrinking keeps the remaining segments. */
+  [cell setSegmentCount: 2];
+  pass([cell segmentCount] == 2 && [[cell labelForSegment: 1] isEqualToString: @"Two"],
+    "shrinking the count keeps the remaining segments");
+
+  /* Segment style. */
+  [cell setSegmentStyle: NSSegmentStyleRounded];
+  pass([cell segmentStyle] == NSSegmentStyleRounded, "setSegmentStyle: round trips");
+
+  END_SET("NSSegmentedCell model")
+
+  DESTROY(arp);
+  return 0;
+}