add ability to select values in the showRowsDialog, fixes #7444

rcp/src/test/java/org/apache/hop/ui/core/dialog/ShowRowsDialogCellSelectionTest.java

@@ -0,0 +1,185 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hop.ui.core.dialog;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Supplier;
+import org.apache.hop.core.row.IRowMeta;
+import org.apache.hop.core.row.RowMeta;
+import org.apache.hop.core.row.value.ValueMetaString;
+import org.apache.hop.core.variables.Variables;
+import org.apache.hop.ui.testing.SwtBotTestBase;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.graphics.Rectangle;
+import org.eclipse.swt.widgets.Control;
+import org.eclipse.swt.widgets.Event;
+import org.eclipse.swt.widgets.Shell;
+import org.eclipse.swt.widgets.Table;
+import org.eclipse.swt.widgets.TableItem;
+import org.eclipse.swt.widgets.Text;
+import org.eclipse.swtbot.swt.finder.SWTBot;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Guards in-place cell selection in {@link ShowRowsDialog}: clicking a cell must drop a read-only,
+ * selectable text field on it that holds the cell's <em>full</em> value, so it can be copied even
+ * when the grid only shows a truncated, single-lined version.
+ *
+ * <p>This is the behaviour the transform/hop "output data" preview lost when it moved off {@link
+ * PreviewRowsDialog} (which has the same click-to-select editor) onto the simpler {@code
+ * ShowRowsDialog}. Without the editor, the click delivered below leaves no {@link Text} on the
+ * table and the assertions here fail.
+ */
+@Tag("uitest")
+class ShowRowsDialogCellSelectionTest extends SwtBotTestBase {
+
+  // Longer than the max preview cell length, so the grid truncates it but the editor must not.
+  private static final String LONG_VALUE =
+      "a very long value that the preview grid truncates for display but must stay selectable "
+          + "in full so it can be copied out of the cell without any characters being lost at all";
+
+  @Test
+  void clickingACellDropsAReadOnlyEditorHoldingTheFullValue() {
+    IRowMeta rowMeta = new RowMeta();
+    rowMeta.addValueMeta(new ValueMetaString("text"));
+    List<Object[]> rows = new ArrayList<>();
+    rows.add(new Object[] {LONG_VALUE});
+
+    withDialog(
+        parent ->
+            new ShowRowsDialog(parent, new Variables(), "Preview", "Output rows", rowMeta, rows)
+                .open(),
+        bot -> {
+          Table table = awaitTable(bot);
+          assertNotNull(table, "the ShowRowsDialog table should open");
+
+          clickFirstDataCell(table);
+
+          Text editor = awaitCellEditor(bot, table);
+          assertNotNull(
+              editor,
+              "clicking a cell should drop a selectable text field holding the value in place");
+          assertTrue(
+              (onUi(editor::getStyle) & SWT.READ_ONLY) != 0,
+              "the in-place cell editor must be read-only (a viewer, not an editor)");
+          assertEquals(
+              LONG_VALUE,
+              onUi(editor::getText),
+              "the editor must expose the full, untruncated cell value for copying");
+        });
+  }
+
+  /** Fires a left mouse-down at the centre of the first data cell (row 0, first value column). */
+  private void clickFirstDataCell(Table table) {
+    onUi(
+        () -> {
+          TableItem item = table.getItem(0);
+          Rectangle bounds = item.getBounds(1); // column 0 is the row number
+          Event event = new Event();
+          event.button = 1;
+          event.x = bounds.x + bounds.width / 2;
+          event.y = bounds.y + bounds.height / 2;
+          table.notifyListeners(SWT.MouseDown, event);
+          return null;
+        });
+  }
+
+  /** Polls for the ShowRowsDialog's table across the open shells. */
+  private Table awaitTable(SWTBot bot) {
+    for (int attempt = 0; attempt < 40; attempt++) {
+      Table found = onUi(ShowRowsDialogCellSelectionTest::findTableOnUi);
+      if (found != null) {
+        return found;
+      }
+      bot.sleep(50);
+    }
+    return null;
+  }
+
+  /** Polls for the read-only editor the click drops directly on the table. */
+  private Text awaitCellEditor(SWTBot bot, Table table) {
+    for (int attempt = 0; attempt < 40; attempt++) {
+      Text found = onUi(() -> findDirectTextChild(table));
+      if (found != null) {
+        return found;
+      }
+      bot.sleep(50);
+    }
+    return null;
+  }
+
+  private static Table findTableOnUi() {
+    for (Shell openShell : display.getShells()) {
+      Table found = findTable(openShell);
+      if (found != null) {
+        return found;
+      }
+    }
+    return null;
+  }
+
+  private static Table findTable(org.eclipse.swt.widgets.Composite parent) {
+    for (Control child : parent.getChildren()) {
+      if (child instanceof Table table) {
+        return table;
+      }
+      if (child instanceof org.eclipse.swt.widgets.Composite composite) {
+        Table found = findTable(composite);
+        if (found != null) {
+          return found;
+        }
+      }
+    }
+    return null;
+  }
+
+  /** The cell editor is a {@link Text} parented straight onto the table (via a TableEditor). */
+  private static Text findDirectTextChild(Table table) {
+    for (Control child : table.getChildren()) {
+      if (child instanceof Text text && !text.isDisposed()) {
+        return text;
+      }
+    }
+    return null;
+  }
+
+  /** Runs {@code supplier} on the UI thread and hands its result back to the SWTBot worker. */
+  private static <T> T onUi(Supplier<T> supplier) {
+    AtomicReference<T> result = new AtomicReference<>();
+    AtomicReference<RuntimeException> failure = new AtomicReference<>();
+    display.syncExec(
+        () -> {
+          try {
+            result.set(supplier.get());
+          } catch (RuntimeException e) {
+            failure.set(e);
+          }
+        });
+    if (failure.get() != null) {
+      throw failure.get();
+    }
+    return result.get();
+  }
+}