fail("Should throw IllegalArgumentException for null engine");
        } catch (IllegalArgumentException e) {
            assertEquals("name or scriptEngine is null.", e.getMessage());
        }
    }

    // Test add method with both null parameters
    public void test_add_bothNull() {
        try {
            scriptEngineFactory.add(null, null);

    }

    // Test execute method with non-BooleanQuery (should throw exception)
    public void test_execute_withNonBooleanQuery() {
        TermQuery termQuery = new TermQuery(new Term("field", "value"));
        QueryContext context = new QueryContext("test", false);

        try {
            booleanQueryCommand.execute(context, termQuery, 1.0f);
            fail("Should throw InvalidQueryException");

        assertTrue(config.isUseUnicode(), "Unicode should be enabled");
        assertTrue(config.isUseBatching(), "Batching should be enabled");

        // When both are enabled, batch limits should be available
        int limit = config.getBatchLimit("TreeConnectAndX.QueryInformation");
        assertTrue(limit >= 0, "Batch limit should be non-negative when Unicode and batching enabled");
    }

    /**

        assertTrue(resp instanceof ServerMessageBlock2);
    }

    @Test
    @DisplayName("Should return correct OVERHEAD constant value")
    void testOverheadConstant() {
        // Then
        assertEquals(Smb2Constants.SMB2_HEADER_LENGTH + 16, Smb2ReadResponse.OVERHEAD);
    }

    @Test
    @DisplayName("Should initially have zero data length")
    void testInitialDataLength() {
        // Then

        NdrShort ns = new NdrShort(original);
        buf.reset();
        ns.encode(buf); // should not throw

        // After encoding, check how many bytes were used
        int bytesUsed = buf.getIndex();
        // Should be 2 bytes for the short value (alignment may add padding)
        assertTrue(bytesUsed >= 2, "Should use at least 2 bytes for short");

        // Reset index to read back
        buf.reset();

        validator.addToBlacklist("\\share\\forbidden");

        // Should block blacklisted path
        try {
            validator.validatePath("\\share\\forbidden\\file.txt");
            fail("Should block blacklisted path");
        } catch (SmbException e) {
            assertTrue(e.getMessage().contains("not allowed"));
        }

        // Should allow other paths

    void testGetConfig() {
        when(smbTreeHandle.getConfig()).thenReturn(mockConfig);
        Configuration config = smbTreeHandle.getConfig();
        assertNotNull(config, "Configuration should not be null");
        assertEquals(mockConfig, config, "Should return the mock Configuration object");
    }

    /**
     * Test for close() method.
     * Verifies that the close method can be called without throwing an exception.

            // key3 should definitely exist (just created)
            assertNotNull(limitedManager.getLease(key3));

            // key1 should have been evicted (oldest)
            assertNull(limitedManager.getLease(key1));

            // key2 should still exist (not the oldest)
            assertNotNull(limitedManager.getLease(key2));
        } finally {

            assertEquals(0x00000008, ACE.FILE_READ_EA, "FILE_READ_EA should be 0x00000008");
            assertEquals(0x00000010, ACE.FILE_WRITE_EA, "FILE_WRITE_EA should be 0x00000010");
            assertEquals(0x00000020, ACE.FILE_EXECUTE, "FILE_EXECUTE should be 0x00000020");
            assertEquals(0x00000040, ACE.FILE_DELETE, "FILE_DELETE should be 0x00000040");

In this case, you could want to document how that external API *should* look like. What *path operation* it should have, what body it should expect, what response it should return, etc.

## An app with callbacks { #an-app-with-callbacks }

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.