5 Common Mistakes To Avoid In Python Automation Testing

Python is a versatile language that is widely used for software development, data analysis, web development, and many other applications. It is known for its simplicity and ease of learning, making it a popular choice for beginners and experienced programmers alike. However, some programmers who are new to the language can be misled by their experience with other core programming languages like Java, C++, or C#.

One of the biggest challenges for programmers who are new to Python is learning to work with its unique features and libraries. Python has a wealth of libraries and tools that can simplify complex tasks and help you perform automation testing to automate repetitive processes.

But these resources can be overwhelming for newcomers. It is important for new Python programmers to take the time to explore the language’s features and capabilities, and to learn how to use its libraries and tools effectively.


What is Python?

Python is a high-level programming language that is interpreted and object-oriented, with dynamic semantics. Its built-in data structures, dynamic typing, and binding make it ideal for Rapid Application Development, as well as for scripting or connecting existing components. Python’s syntax is simple and easy to learn, with an emphasis on readability, which reduces the cost of program maintenance.

Additionally, Python supports modules and packages, which promote program modularity and code reuse. Python is available for all major platforms in both source and binary form, and its interpreter and extensive standard library can be distributed freely.

Keynote Features of Python

  • With no prior coding experience one can grasp the basics of Python in just a few hours or days. While mastering more advanced Python concepts and features may take longer, the language’s basic syntax is far simpler to understand than that of other commonly used programming languages such as C, C++, and Java.
  • Python code is highly legible as it resembles plain English words, with no need for brackets or semicolons, and code blocks are defined by indentations. With just a glance, you can easily comprehend what the code is meant to achieve.
  • Python is governed by an open source license approved by the Open Source Initiative (OSI), making it free to use, even for commercial purposes. There are no charges associated with downloading Python or incorporating it into your software application. Moreover, Python can be modified and distributed without any restrictions. The official Python website is the best source for downloading the language.
  • Python boasts a robust standard library that programmers can readily utilize, eliminating the need to write custom code for every single task as is often the case with other programming languages. The standard library offers a wide range of functionality, including image manipulation, databases, unit-testing, expressions, and much more.
  • Interpreted programming languages execute source code line by line instead of all at once. Unlike interpreted languages, languages like C++ or Java must be compiled before they can run. Python, on the other hand, does not require compilation as it is processed at runtime by the interpreter.

Common mistakes to avoid in Python Testing


1. Using expressions as default values for function arguments

When writing functions, beginners often make the common mistake of using expressions as default values for function arguments. Although this error may not cause any errors initially and may work fine in simple cases, it can create issues in more complex workspaces.

The problem arises when a mutable optional argument is specified, which means that if a function is called without that argument, the function will create a new instance of that mutable object. However, if the argument is not optional and is not provided, it will raise an error.

In Python, default arguments are evaluated only once, i.e., during the function definition. In the first call, the default argument (an empty list) is used.

To avoid such issues, it is recommended to use immutable objects as default arguments, such as None. If a mutable object is required as a default argument, it is best to use the default argument value as None and initialize the object inside the function,

2. Clashes in module names

A common issue that arises in programming discussions is the problem of module name clashes in Python. This occurs when a programmer unintentionally uses the same name for a module as a pre-existing module in Python’s standard library. This mistake can cause errors and make it difficult to properly import and use the desired module.

Module name clashes can be particularly challenging to resolve in complex projects with many dependencies. To avoid these issues, it is important to use unique and descriptive names for your own modules and to be mindful of potential conflicts with existing modules. Additionally, using absolute and relative module paths in imports can help mitigate issues related to module name clashes.

3. Improper Use of the init Method

Improper use of the init method in Python classes can lead to unexpected behavior and errors in the code. The init method is a special method that is automatically invoked when a new instance of a class is created, and its primary purpose is to initialize the attributes of the class object.

Some programmers mistakenly use the init method to return a value from the constructor, which is not its intended purpose. The init method is meant to assign values to instance members of the class object, not to return a value.

When the init method is misused, it can lead to errors such as TypeErrors or AttributeErrors, which can be difficult to diagnose and resolve. Therefore, it is essential to use the init method as intended, and to avoid attempting to return values from it.

Proper use of the init method involves initializing instance variables, setting default values for optional arguments, and performing any necessary setup for the class object. By using the init method correctly, you can ensure that your code runs smoothly and is free from unexpected errors.

4. Using assert statements as a form of guarding condition

Assert statements in Python are commonly used to check conditions and trigger an error if the condition is not satisfied. Developers often use assert statements as a form of guarding condition, i.e., to ensure that a particular condition holds true before executing a block of code. However, it is essential to use assert statements with caution and limit their use to testing only.

The reason for this is that when running Python with the -o flag (optimize), the assert statements are removed from the bytecode. This means that any assert statements used in production code to validate a condition will not be executed, and the corresponding code block will be skipped entirely. This behavior can lead to unexpected and potentially dangerous outcomes, such as allowing invalid input to slip through, resulting in data corruption or a security vulnerability.

Therefore, it is advisable to limit the use of assert statements to testing only, where their purpose is to catch errors during development and debugging. When using assert statements in test code, it is important to ensure that the conditions being tested are relevant and significant. Overusing assert statements can clutter code and make it difficult to maintain and debug.

In summary, while assert statements can be a useful tool for checking conditions and halting execution when necessary, their use should be limited to testing only. Careful consideration should be given to the conditions being tested, and assert statements should be used sparingly and thoughtfully to ensure that code remains secure and bug-free.

5. Modifying a collection while iterating through it

It is a common scenario for developers to try to modify a collection, such as a list or dictionary, while iterating through it in Python. This occurs when a programmer needs to make changes to a collection based on certain conditions or criteria, such as filtering out certain elements or updating their values.

However, modifying a collection while iterating through it can lead to unexpected results and errors. This is because the length and indices of the collection can change as elements are added or removed, which can cause the iteration to skip over or double-count elements, or even result in the program crashing due to an index error.


Therefore, it is important to use caution when modifying collections during an iteration in Python. One way to avoid issues is to create a copy of the collection and modify the copy instead of the original. Another approach is to use list comprehension or other built-in functions, such as filter() and map(), to create a new collection based on the criteria without modifying the original.

Overall, while it may be tempting to modify a collection during iteration, it is important to be aware of the potential consequences and use safe practices to avoid errors and ensure the intended behavior of the program.

LambdaTest is a cloud-based digital experience testing platform that allows developers to perform Python automation testing with Selenium on a wide range of browsers and operating systems. LambdaTest can be a useful tool for identifying and diagnosing errors that may be related to web applications written in Python.

When using LambdaTest, developers can run their web applications on a variety of browsers and platforms, allowing them to identify any issues that may be caused by differences in browser behavior or compatibility issues. This can help developers diagnose and resolve errors more quickly and efficiently, improving the overall quality and performance of their applications.


Newcomers to Python often make certain mistakes that can be avoided with a better understanding of the language’s key nuances. By becoming more familiar with these nuances, you can optimize your use of Python and reduce the likelihood of running into common errors.

Therefore, it is important to invest time in learning the ins and outs of Python to ensure that you are using the language to its fullest potential. This includes familiarizing yourself with concepts such as data types, control flow statements, and functions, as well as best practices for coding in Python.

By doing so, you can avoid common mistakes and write more efficient and effective code. Additionally, a deeper understanding of Python can lead to greater creativity and innovation in your programming projects, allowing you to push the boundaries of what is possible with the language.

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