feat: add MailSync process wrapper

Runs the configured sync script through QProcess, merging stdout and
stderr into one log so a failing mbsync run has something to show. The
script is never run through a shell: the command is a config value, and
splitCommand keeps its arguments literal.

Two fixes against the drafted version:

- start() no longer calls waitForStarted(). It blocked the UI thread for
  up to five seconds, which contradicts the spec's requirement that the UI
  stay usable during sync, and it swallowed launch failures into a bare
  false return. A missing script now surfaces asynchronously through
  errorOccurred as finished(false, -1) with an explanatory log line, so
  the spinner cannot hang with nothing to explain it.
- Removed a double-emit guard I had added on the assumption that QProcess
  follows errorOccurred(FailedToStart) with finished(). Verified it does
  not: FailedToStart is emitted instead of finished, never before it. The
  guard was dead state and the comment justifying it was wrong.

Also corrects the sync interval throughout: the user's cron runs every 10
minutes, not hourly. The shorter interval strengthens the flock rationale
rather than weakening it, since collisions with a manual sync are that
much more likely.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 239 insertions, 0 deletions

diff --git a/tests/test_mailsync.cpp b/tests/test_mailsync.cpp
new file mode 100644
index 0000000..cb8d454
--- /dev/null
+++ b/tests/test_mailsync.cpp
@@ -0,0 +1,239 @@
+#include <QElapsedTimer>
+#include <QFile>
+#include <QSignalSpy>
+#include <QTemporaryDir>
+#include <QtTest>
+
+#include "mailsync.h"
+
+class TestMailSync : public QObject
+{
+    Q_OBJECT
+private slots:
+    void initTestCase();
+
+    void unavailableWhenCommandEmpty();
+    void unavailableWhenCommandIsOnlyWhitespace();
+    void successfulRunEmitsFinished();
+    void failedRunReportsExitCode();
+    void capturesOutput();
+    void capturesStderrToo();
+    void emitsStartedSignal();
+    void logIsClearedBetweenRuns();
+    void refusesConcurrentRuns();
+    void canRunAgainAfterFinishing();
+    void missingBinaryReportsFailureNotSilence();
+    void startDoesNotBlock();
+    void argumentsAreNotShellInterpreted();
+
+private:
+    /// Writes an executable shell script into the temp dir, returns its path.
+    QString makeScript(const QString &name, const QString &body);
+
+    QTemporaryDir m_dir;
+};
+
+void TestMailSync::initTestCase()
+{
+    QVERIFY(m_dir.isValid());
+}
+
+QString TestMailSync::makeScript(const QString &name, const QString &body)
+{
+    const QString path = m_dir.filePath(name);
+    QFile file(path);
+    if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
+        return QString();
+    file.write("#!/bin/sh\n");
+    file.write(body.toUtf8());
+    file.write("\n");
+    file.close();
+    file.setPermissions(QFile::ReadOwner | QFile::WriteOwner | QFile::ExeOwner);
+    return path;
+}
+
+void TestMailSync::unavailableWhenCommandEmpty()
+{
+    // Braces, not parens: MailSync sync(QString()) is a function declaration.
+    MailSync sync{ QString() };
+    QVERIFY(!sync.isAvailable());
+    QVERIFY(!sync.start());
+}
+
+void TestMailSync::unavailableWhenCommandIsOnlyWhitespace()
+{
+    // A config line like `command =   ` reaches here as spaces, not as empty.
+    // splitCommand yields nothing for it, so start() must refuse rather than
+    // try to launch an empty program name.
+    MailSync sync(QStringLiteral("   "));
+    QVERIFY(!sync.start());
+    QVERIFY(!sync.isRunning());
+}
+
+void TestMailSync::successfulRunEmitsFinished()
+{
+    MailSync sync(makeScript(QStringLiteral("ok.sh"), QStringLiteral("exit 0")));
+    QVERIFY(sync.isAvailable());
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+
+    QCOMPARE(spy.count(), 1);
+    QCOMPARE(spy.first().at(0).toBool(), true);
+    QCOMPARE(spy.first().at(1).toInt(), 0);
+}
+
+void TestMailSync::failedRunReportsExitCode()
+{
+    MailSync sync(makeScript(QStringLiteral("fail.sh"), QStringLiteral("exit 3")));
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+
+    QCOMPARE(spy.first().at(0).toBool(), false);
+    // The exit code reaches the UI: the status bar shows why sync failed.
+    QCOMPARE(spy.first().at(1).toInt(), 3);
+}
+
+void TestMailSync::capturesOutput()
+{
+    MailSync sync(makeScript(QStringLiteral("talk.sh"),
+                             QStringLiteral("echo syncing")));
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QSignalSpy output(&sync, &MailSync::outputReceived);
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+
+    QVERIFY(sync.log().contains(QStringLiteral("syncing")));
+    QVERIFY(!output.isEmpty());
+}
+
+void TestMailSync::capturesStderrToo()
+{
+    // mbsync reports failures on stderr. If only stdout were captured, the log
+    // pane would be empty for exactly the runs the user needs to read.
+    MailSync sync(makeScript(QStringLiteral("noisy.sh"),
+                             QStringLiteral("echo boom >&2\nexit 1")));
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+
+    QVERIFY(sync.log().contains(QStringLiteral("boom")));
+}
+
+void TestMailSync::emitsStartedSignal()
+{
+    MailSync sync(makeScript(QStringLiteral("started.sh"), QStringLiteral("exit 0")));
+
+    QSignalSpy started(&sync, &MailSync::started);
+    QSignalSpy finished(&sync, &MailSync::finished);
+    QVERIFY(sync.start());
+    QVERIFY(finished.wait(5000));
+
+    QCOMPARE(started.count(), 1);
+}
+
+void TestMailSync::logIsClearedBetweenRuns()
+{
+    MailSync sync(makeScript(QStringLiteral("once.sh"), QStringLiteral("echo first")));
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+    QVERIFY(sync.log().contains(QStringLiteral("first")));
+
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+    // Stale output from the previous run must not accumulate: the log pane is
+    // meant to show what this sync did.
+    QCOMPARE(sync.log().count(QStringLiteral("first")), 1);
+}
+
+void TestMailSync::refusesConcurrentRuns()
+{
+    MailSync sync(makeScript(QStringLiteral("slow.sh"), QStringLiteral("sleep 2")));
+    QVERIFY(sync.start());
+    // The cron sync and this one share a flock; starting twice from the GUI is
+    // still refused locally so the button cannot queue runs.
+    QVERIFY(!sync.start());
+    QVERIFY(sync.isRunning());
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(spy.wait(10000));
+}
+
+void TestMailSync::canRunAgainAfterFinishing()
+{
+    MailSync sync(makeScript(QStringLiteral("again.sh"), QStringLiteral("exit 0")));
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+    QVERIFY(!sync.isRunning());
+
+    // A refusal must be about "currently running", not a one-shot latch.
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+    QCOMPARE(spy.count(), 2);
+}
+
+void TestMailSync::missingBinaryReportsFailureNotSilence()
+{
+    // Config checks the path at load time, but the script can be deleted or
+    // unmounted afterwards. Failing silently would leave the spinner up
+    // forever with no explanation.
+    MailSync sync(m_dir.filePath(QStringLiteral("definitely-not-here.sh")));
+    QVERIFY(sync.isAvailable());
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+
+    QCOMPARE(spy.first().at(0).toBool(), false);
+    QVERIFY(!sync.log().isEmpty());
+    QVERIFY(!sync.isRunning());
+}
+
+void TestMailSync::startDoesNotBlock()
+{
+    // Spec: "The UI stays usable during sync." start() must hand off to the
+    // event loop rather than waiting for the process.
+    MailSync sync(makeScript(QStringLiteral("blocker.sh"), QStringLiteral("sleep 2")));
+
+    QElapsedTimer timer;
+    timer.start();
+    QVERIFY(sync.start());
+    const qint64 elapsed = timer.elapsed();
+
+    QVERIFY2(elapsed < 500,
+             qPrintable(QStringLiteral("start() blocked for %1ms").arg(elapsed)));
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(spy.wait(10000));
+}
+
+void TestMailSync::argumentsAreNotShellInterpreted()
+{
+    // The command comes from a config file. Running it through a shell would
+    // turn that value into an injection point, so the metacharacters below must
+    // arrive at the script as literal arguments.
+    const QString script = makeScript(QStringLiteral("args.sh"),
+                                      QStringLiteral("echo \"$1\""));
+
+    MailSync sync(QStringLiteral("%1 \"; touch %2/pwned\"")
+                      .arg(script, m_dir.path()));
+
+    QSignalSpy spy(&sync, &MailSync::finished);
+    QVERIFY(sync.start());
+    QVERIFY(spy.wait(5000));
+
+    QVERIFY(!QFile::exists(m_dir.filePath(QStringLiteral("pwned"))));
+    QVERIFY(sync.log().contains(QStringLiteral("; touch")));
+}
+
+QTEST_MAIN(TestMailSync)
+#include "test_mailsync.moc"