1 files changed, 96 insertions, 0 deletions
diff --git a/tests/test_maildirname.cpp b/tests/test_maildirname.cpp
index dcc8fab..a8e4c01 100644
--- a/tests/test_maildirname.cpp
+++ b/tests/test_maildirname.cpp
@@ -18,7 +18,10 @@
 
 #include "maildirname.h"
 
+#include <QDir>
+#include <QFile>
 #include <QSet>
+#include <QTemporaryDir>
 #include <QTest>
 
 class TestMaildirName : public QObject
@@ -31,6 +34,11 @@ private slots:
     void anEmptyFlagSuffixIsPreserved();
     void aNameWithNoSuffixGetsNone();
     void theUidInfixIsNotCarriedAcross();
+    void resolveRenamedReturnsAPathThatStillExists();
+    void resolveRenamedFindsTheFileMbsyncRenamed();
+    void resolveRenamedIsEmptyWhenTheFileIsReallyGone();
+    void resolveRenamedDoesNotMatchADifferentMessage();
+    void resolveRenamedRefusesAnAmbiguousMatch();
 };
 
 // Two messages written in the same second must not collide, which a
@@ -89,5 +97,93 @@ void TestMaildirName::theUidInfixIsNotCarriedAcross()
                             .arg(name)));
 }
 
+namespace {
+
+/// One empty file, so a test can assert on which PATH is chosen rather than on
+/// content. resolveRenamed() answers a filesystem question and never opens the
+/// file.
+bool touch(const QString &path)
+{
+    QFile file(path);
+    if (!file.open(QIODevice::WriteOnly))
+        return false;
+    file.close();
+    return true;
+}
+
+}  // namespace
+
+void TestMaildirName::resolveRenamedReturnsAPathThatStillExists()
+{
+    // The ordinary case, and the one that must stay cheap: nothing was
+    // renamed, so the answer is the question.
+    QTemporaryDir dir;
+    QVERIFY(dir.isValid());
+
+    const QString path = dir.filePath(QStringLiteral("1787647354.M369Q2.host:2,D"));
+    QVERIFY(touch(path));
+
+    QCOMPARE(MaildirName::resolveRenamed(path), path);
+}
+
+void TestMaildirName::resolveRenamedFindsTheFileMbsyncRenamed()
+{
+    // Item 163. mbsync uploads the file and inserts its `,U=<uid>` infix
+    // before the flag suffix, leaving the unique stem alone.
+    QTemporaryDir dir;
+    QVERIFY(dir.isValid());
+
+    const QString stale = dir.filePath(QStringLiteral("1787647354.M369Q2.host:2,D"));
+    const QString renamed =
+        dir.filePath(QStringLiteral("1787647354.M369Q2.host,U=5:2,D"));
+    QVERIFY(touch(renamed));
+    QVERIFY2(!QFile::exists(stale), "the stale path must not exist");
+
+    QCOMPARE(MaildirName::resolveRenamed(stale), renamed);
+}
+
+void TestMaildirName::resolveRenamedIsEmptyWhenTheFileIsReallyGone()
+{
+    // The bounded half. A deleted file must NOT be recovered from, or a
+    // reportable defect becomes a wrong answer.
+    QTemporaryDir dir;
+    QVERIFY(dir.isValid());
+
+    const QString gone = dir.filePath(QStringLiteral("1787647354.M369Q2.host:2,D"));
+    QVERIFY(!QFile::exists(gone));
+
+    QVERIFY(MaildirName::resolveRenamed(gone).isEmpty());
+}
+
+void TestMaildirName::resolveRenamedDoesNotMatchADifferentMessage()
+{
+    // A neighbouring file in the same folder is not this message. Matching on
+    // anything looser than the whole stem would return it, and the caller
+    // would then open, display or MOVE the wrong mail.
+    QTemporaryDir dir;
+    QVERIFY(dir.isValid());
+
+    const QString stale = dir.filePath(QStringLiteral("1787647354.M369Q2.host:2,D"));
+    QVERIFY(touch(dir.filePath(QStringLiteral("1787647354.M369Q3.host,U=5:2,D"))));
+    QVERIFY(touch(dir.filePath(QStringLiteral("9999999999.M111Q1.host,U=6:2,D"))));
+
+    QVERIFY(MaildirName::resolveRenamed(stale).isEmpty());
+}
+
+void TestMaildirName::resolveRenamedRefusesAnAmbiguousMatch()
+{
+    // Two files sharing one stem cannot happen in a correct Maildir, so this
+    // is a "the world is not what I assumed" case. Guessing between them could
+    // move or delete the wrong file, and the caller reports honestly instead.
+    QTemporaryDir dir;
+    QVERIFY(dir.isValid());
+
+    const QString stale = dir.filePath(QStringLiteral("1787647354.M369Q2.host:2,D"));
+    QVERIFY(touch(dir.filePath(QStringLiteral("1787647354.M369Q2.host,U=5:2,D"))));
+    QVERIFY(touch(dir.filePath(QStringLiteral("1787647354.M369Q2.host,U=6:2,S"))));
+
+    QVERIFY(MaildirName::resolveRenamed(stale).isEmpty());
+}
+
 QTEST_MAIN(TestMaildirName)
 #include "test_maildirname.moc"