lib: improve test coverage

Add a bunch of tests

lib/tests/test-mu-maildir.cc

@@ -278,6 +278,77 @@ test_determine_target_ok(void)
 }
 
 
+
+static void
+test_determine_target_fail(void)
+{
+	struct TestCase {
+		std::string old_path;
+		std::string root_maildir;
+		std::string target_maildir;
+		Flags new_flags;
+		bool new_name;
+		std::string expected;
+	};
+	const std::vector<TestCase> testcases = {
+		 TestCase{ /* fail: no absolute path */
+			"../foo/Maildir/test/cur/123456:2,FR-not-absolute",
+			"/home/foo/Maildir",
+			{},
+			Flags::Seen | Flags::Passed,
+			false,
+			"/home/foo/Maildir/test/cur/123456:2,PS"
+		},
+
+		 TestCase{ /* fail: no absolute root */
+			"/home/foo/Maildir/test/cur/123456:2,FR",
+			"../foo/Maildir-not-absolute",
+			{},
+			Flags::New,
+			false,
+			"/home/foo/Maildir/test/new/123456"
+		},
+
+		 TestCase{ /* fail: maildir must start with '/' */
+			"/home/foo/Maildir/test/cur/123456",
+			"/home/foo/Maildir",
+			"mymaildirwithoutslash",
+			Flags::Seen | Flags::Flagged,
+			false,
+			"/home/foo/Maildir/test/cur/123456:2,FS"
+		 },
+
+		 TestCase{ /* fail: path must be below maildir */
+			"/home/foo/Maildir/test/cur/123456:2,FR",
+			"/home/bar/Maildir",
+			"/test2",
+			Flags::Flagged | Flags::Replied,
+			false,
+			"/home/foo/Maildir/test2/cur/123456:2,FR"
+		},
+		 TestCase{ /* fail: New cannot be combined */
+			"/home/foo/Maildir/test/new/123456",
+			"/home/foo/Maildir",
+			{},
+			Flags::New | Flags::Replied,
+			false,
+			"/home/foo/Maildir/test/cur/123456:2,"
+		},
+	};
+
+	for (auto&& testcase: testcases) {
+		const auto res = maildir_determine_target(
+			testcase.old_path,
+			testcase.root_maildir,
+			testcase.target_maildir,
+			testcase.new_flags,
+			testcase.new_name);
+		g_assert_false(!!res);
+	}
+}
+
+
+
 static void
 test_maildir_get_new_path_01(void)
 {
@@ -428,6 +499,8 @@ main(int argc, char* argv[])
 
 	g_test_add_func("/mu-maildir/mu-maildir-determine-target-ok",
 			test_determine_target_ok);
+	g_test_add_func("/mu-maildir/mu-maildir-determine-target-fail",
+			test_determine_target_fail);
 
 	// /* get/set flags */
 	g_test_add_func("/mu-maildir/mu-maildir-get-new-path-01", test_maildir_get_new_path_01);

lib/tests/test-mu-store.cc

@@ -139,6 +139,12 @@ goto * instructions[pOp->opcode];
 	assert_valid_result(docid);
 	g_assert_cmpuint(store->size(),==, 1);
 
+	/* ensure 'update' dtrt, i.e., nothing. */
+	const auto docid2 = store->update_message(*message, *docid);
+	assert_valid_result(docid2);
+	g_assert_cmpuint(store->size(),==, 1);
+	g_assert_cmpuint(*docid,==,*docid2);
+
 	auto msg2{store->find_message(*docid)};
 	g_assert_true(!!msg2);
 	assert_equal(message->path(), msg2->path());
@@ -228,6 +234,11 @@ World!
 	// for (auto&& term = msg2->document().xapian_document().termlist_begin();
 	//      term != msg2->document().xapian_document().termlist_end(); ++term)
 	//	g_message(">>> %s", (*term).c_str());
+
+	const auto stats{store->statistics()};
+	g_assert_cmpuint(stats.size,==,store->size());
+	g_assert_cmpuint(stats.last_index,==,0);
+	g_assert_cmpuint(stats.last_change,>=,::time({}));
 }
 
 
@@ -319,6 +330,23 @@ Yes, that would be excellent.
 }
 
 
+static void
+test_store_fail()
+{
+	{
+		const auto store = Store::make("/root/non-existent-path/12345");
+		g_assert_false(!!store);
+	}
+
+	{
+		const auto store = Store::make_new("/../../root/non-existent-path/12345",
+						   "/../../root/non-existent-path/54321",
+						   {}, {});
+		g_assert_false(!!store);
+
+	}
+}
+
 
 int
 main(int argc, char* argv[])
@@ -331,8 +359,8 @@ main(int argc, char* argv[])
 			test_message_mailing_list);
 	g_test_add_func("/store/message/attachments",
 			test_message_attachments);
-	g_test_add_func("/store/index/move",
-			test_index_move);
+	g_test_add_func("/store/index/move", test_index_move);
+	g_test_add_func("/store/index/fail", test_store_fail);
 
 	if (!g_test_verbose())
 		g_log_set_handler(