tests: add NSTextAttachment tests

ChangeLog

@@ -37,6 +37,14 @@
 	size, postscript name and matrix extractors, and the descriptor
 	derivation methods.
 
+2026-07-12 Todd White <todd.white@thalion.global>
+
+	* Tests/gui/NSTextAttachment/basic.m:
+	* Tests/gui/NSTextAttachment/TestInfo:
+	Add tests for NSTextAttachment: the default attachment cell, the file
+	wrapper round-trip and the attachment cell round-trip with its back
+	reference.
+
 2026-07-12 Todd White <todd.white@thalion.global>
 
 	* Tests/gui/NSTextContainer/basic.m:

Tests/gui/NSTextAttachment/basic.m

@@ -0,0 +1,71 @@
+/* Coverage for NSTextAttachment: the default attachment cell, the file
+ * wrapper round-trip, and the attachment cell round-trip with its back
+ * reference to the attachment.  Setting a file wrapper reaches the file
+ * icon, so the set uses the backend and is skipped when it is unavailable.
+ */
+#include "Testing.h"
+#include <Foundation/Foundation.h>
+#include <AppKit/NSApplication.h>
+#include <AppKit/NSTextAttachment.h>
+
+int
+main(int argc, char **argv)
+{
+  CREATE_AUTORELEASE_POOL(arp);
+  NSData *data = [@"hello" dataUsingEncoding: NSUTF8StringEncoding];
+  NSFileWrapper *fw = AUTORELEASE([[NSFileWrapper alloc]
+    initRegularFileWithContents: data]);
+
+  START_SET("NSTextAttachment")
+
+  NS_DURING
+  {
+    [NSApplication sharedApplication];
+  }
+  NS_HANDLER
+  {
+    if ([[localException name] isEqualToString: NSInternalInconsistencyException])
+      SKIP("It looks like GNUstep backend is not yet installed")
+  }
+  NS_ENDHANDLER
+
+  {
+    NSTextAttachment *a = AUTORELEASE([[NSTextAttachment alloc]
+      initWithFileWrapper: nil]);
+
+    pass([a fileWrapper] == nil, "an attachment with no wrapper has none");
+    pass([(id)[a attachmentCell] isKindOfClass: [NSTextAttachmentCell class]],
+         "an attachment has a text attachment cell by default");
+  }
+
+  {
+    NSTextAttachment *a = AUTORELEASE([[NSTextAttachment alloc]
+      initWithFileWrapper: fw]);
+
+    pass([a fileWrapper] == fw, "initWithFileWrapper: stores the wrapper");
+    pass([(id)[a attachmentCell] isKindOfClass: [NSTextAttachmentCell class]],
+         "an attachment from a wrapper still has a cell");
+  }
+
+  {
+    NSTextAttachment *a = AUTORELEASE([[NSTextAttachment alloc] init]);
+
+    [a setFileWrapper: fw];
+    pass([a fileWrapper] == fw, "setFileWrapper: round trips");
+  }
+
+  {
+    NSTextAttachment *a = AUTORELEASE([[NSTextAttachment alloc] init]);
+    NSTextAttachmentCell *cell = AUTORELEASE([[NSTextAttachmentCell alloc] init]);
+
+    [a setAttachmentCell: cell];
+    pass([a attachmentCell] == cell, "setAttachmentCell: round trips");
+    pass([cell attachment] == a,
+         "setAttachmentCell: points the cell back at the attachment");
+  }
+
+  END_SET("NSTextAttachment")
+
+  DESTROY(arp);
+  return 0;
+}