feat(completion): add the query cursor-context tokenizer

Prefix completion only so far: the token under the cursor, bounded by
whitespace or an opening parenthesis rather than by the start of the line.

1 files changed, 66 insertions, 0 deletions

diff --git a/tests/test_querycompleter.cpp b/tests/test_querycompleter.cpp
new file mode 100644
index 0000000..9278a1e
--- /dev/null
+++ b/tests/test_querycompleter.cpp
@@ -0,0 +1,66 @@
+/*
+ * qtmaildir - a Qt6 mail client for notmuch-indexed Maildirs
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <QtTest>
+
+#include "querycompleter.h"
+
+class TestQueryCompleter : public QObject
+{
+    Q_OBJECT
+
+private slots:
+    void emptyTextCompletesPrefix();
+    void bareWordCompletesPrefix();
+    void wordAfterOperatorCompletesPrefix();
+    void prefixReplaceSpanCoversTheWord();
+};
+
+void TestQueryCompleter::emptyTextCompletesPrefix()
+{
+    const CompletionContext ctx = completionContext(QString(), 0);
+    QCOMPARE(ctx.kind, CompletionContext::Prefix);
+    QCOMPARE(ctx.stem, QString());
+}
+
+void TestQueryCompleter::bareWordCompletesPrefix()
+{
+    const CompletionContext ctx = completionContext(QStringLiteral("su"), 2);
+    QCOMPARE(ctx.kind, CompletionContext::Prefix);
+    QCOMPARE(ctx.stem, QStringLiteral("su"));
+}
+
+void TestQueryCompleter::wordAfterOperatorCompletesPrefix()
+{
+    // The token boundary is whitespace, not the start of the line.
+    const QString text = QStringLiteral("tag:inbox and su");
+    const CompletionContext ctx = completionContext(text, text.size());
+    QCOMPARE(ctx.kind, CompletionContext::Prefix);
+    QCOMPARE(ctx.stem, QStringLiteral("su"));
+}
+
+void TestQueryCompleter::prefixReplaceSpanCoversTheWord()
+{
+    const QString text = QStringLiteral("tag:inbox and su");
+    const CompletionContext ctx = completionContext(text, text.size());
+    QCOMPARE(ctx.replaceFrom, 14);
+    QCOMPARE(ctx.replaceLength, 2);
+}
+
+QTEST_MAIN(TestQueryCompleter)
+#include "test_querycompleter.moc"