assertNotNull(context.getNameServiceClient(), "Name service client should be initialized");
        assertNotNull(context.getBufferCache(), "Buffer cache should be initialized");
        assertNotNull(context.getTransportPool(), "Transport pool should be initialized");
    }

    @Test
    @DisplayName("Constructor should use provided configuration")

        // Then - Buffer should have expected size
        assertNotNull(buffer, "Buffer should not be null");
        assertEquals(SmbComTransaction.TRANSACTION_BUF_SIZE, buffer.length, "Buffer should have TRANSACTION_BUF_SIZE");

        // The validation in getBuffer() ensures size is within bounds (0 < size <= 1MB)
        assertTrue(buffer.length > 0, "Buffer size should be positive");

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.

        assertNotNull(request);
        // The request should be properly created - we can't easily verify headers without mocking framework
    }

    public void test_post() {
        setupMockConfig("localhost:9200", "", "");

        curlHelper.init();
        CurlRequest request = curlHelper.post("/test");

        assertNotNull(request);
        // The request should be properly created
    }

    public void test_put() {

        String hostName = mockAddress.getHostName();

        // Then
        assertEquals(expectedHostName, hostName, "Should return configured hostname");
        assertNotNull(hostName, "Host name should not be null");
    }

    @Test
    @DisplayName("getHostAddress should return valid IP address string")
    void testGetHostAddressContract() {
        // Given
        String expectedAddress = "192.168.1.100";

        // Then
        assertNotNull(signingKey, "Signing key should not be null");
        assertEquals(16, signingKey.length, "Signing key should be 16 bytes");
        assertFalse(Arrays.equals(sessionKey, signingKey), "Signing key should be different from session key");
    }

    @Test
    @DisplayName("Should derive signing key for SMB 3.1.1 dialect")
    void testDeriveSigningKey_SMB311() {
        // Given

        int bytesRead = response.readParameterWordsWireFormat(buffer, 0);

        // The count should be read from the buffer.
        assertEquals(10L, response.count);
        // The method should return the number of bytes read.
        assertEquals(8, bytesRead);
    }

    /**
     * Test the writeParameterWordsWireFormat method.
     */
    @Test

        // Then
        assertTrue(smb2Only, "Should delegate SMB2 only negotiation");
        assertFalse(secureNegotiate, "Should delegate secure negotiate requirement");
        assertTrue(ntlmTargetName, "Should delegate NTLM target name setting");
        assertFalse(port139Failover, "Should delegate port 139 failover setting");
        assertTrue(dfsStrictView, "Should delegate DFS strict view setting");

            assertNotNull(str, "toString should not return null");
            assertTrue(str.contains("SmbComTreeConnectAndXResponse"), "Should contain class name");
            assertTrue(str.contains("supportSearchBits=true"), "Should contain search bits flag");
            assertTrue(str.contains("shareIsInDfs=true"), "Should contain DFS flag");
            assertTrue(str.contains("service=IPC"), "Should contain service");

		if !DB.Migrator().HasColumn(&EngadgetPost{}, name) {
			t.Errorf("should has prefixed column %v", name)
		}
	}

	stmt := gorm.Statement{DB: DB}
	if err := stmt.Parse(&EngadgetPost{}); err != nil {
		t.Fatalf("failed to parse embedded struct")
	} else if len(stmt.Schema.PrimaryFields) != 1 {
		t.Errorf("should have only one primary field with embedded struct, but got %v", len(stmt.Schema.PrimaryFields))
	}