Magic Number Test

Definition:

• This smell occurs when a test method contains unexplained and undocumented numeric literals as parameters or as values to identifiers. These magic values do not sufficiently indicate the meaning/purpose of the number. Hence, they hinder code understandability. Consequently, they should be replaced with constants or variables, thereby providing a descriptive name for the value.

Code Example:

@Test
public void testGetLocalTimeAsCalendar() {
    Calendar localTime = calc.getLocalTimeAsCalendar(BigDecimal.valueOf(15.5D), Calendar.getInstance());
    assertEquals(15, localTime.get(Calendar.HOUR_OF_DAY));
    assertEquals(30, localTime.get(Calendar.MINUTE));
}

References:

Quality attributes

• - Code Example

• - Cause and Effect

• - Frequency

• - Refactoring

• A survey on test practitioners’ awareness of test smells

• An Exploratory Study on the Refactoring of Unit Test Files in Android Applications

• Analyzing Test Smells Refactoring from a Developers Perspective

• Automatic Identification of High-Impact Bug Report by Product and Test Code Quality

• Automatic generation of smell-free unit tests

• Characterizing High-Quality Test Methods: A First Empirical Study

• Handling Test Smells in Python: Results from a Mixed-Method Study

• How are test smells treated in the wild? A tale of two empirical studies

• Investigating Severity Thresholds for Test Smells

• Investigating Test Smells in JavaScript Test Code

• On the Distribution of “Simple Stupid Bugs” in Unit Test Files: An Exploratory Study

• On the diffusion of test smells and their relationship with test code quality of Java projects

• On the distribution of test smells in open source Android applications: an exploratory study

• On the influence of Test Smells on Test Coverage

• On the test smells detection: an empirical study on the jnose test accuracy

• On the use of test smells for prediction of flaky tests

• PyNose: A Test Smell Detector For Python

• Pytest-Smell: a smell detection tool for Python unit tests

• Refactoring Test Smells: A Perspective from Open-Source Developers

• Software Unit Test Smells

• Test Artifacts — The Practical Testing Book

• Test Smell Detection Tools: A Systematic Mapping Study

• The secret life of test smells-an empirical study on test smell evolution and maintenance

• What the Smell? An Empirical Investigation on the Distribution and Severity of Test Smells in Open Source Android Applications

• tsDetect: an open source test smells detection tool