Path Testing

Path Testing

A vital part of software engineering, testing ensures that no errors or issues exist in the software product that could compromise its safety, security, and even the financial investment of the client or the user. Path Testing, which is executed by the team during software testing life cycle (STLC), helps evaluate and verify various structural aspects of the product that enables the team to guarantee the effectiveness and the quality of the product.

Therefore, to further elaborate on the importance of this testing technique, here is a detailed discussion on path testing and its various components.

Significance of Path in SDLC:

In the field of software development, the term 'Path' describes the flow of the process in a particular direction. It basically defines the route(s) of the process that starts from a particular node and ends at the destination node. A path through a program is the sequence, which begins at one junction and terminates at another.

This concept of path can better be understood with the assistance of a diagram. Suppose, a process initiates at node A and it will be terminated at node I. The path that may be taken by the process to reach its destination are:

AB→C→F→I or A→D→G→H→I or A→E→I, and many more

Further, the intermediate routes such as B to F, D to H, to H, A to E, etc. are also comes under the terminology of 'path'.

What is Path Testing in Software Testing?

Path testing refers to the checking of the paths through various processes, which are involved in the functioning of the software product or application and will later be executed. Basically, it is a type of structural testing that works on the source code.

Path testing follows a process of control flow or workflow, rather than executing the process of testing on the basis of specifications. The main intent behind this type of testing is to ensure that every possible path has been covered and executed at least once, through the software program.

Features of Path Testing

An important software testing technique, path testing helps identify issues in a piece of code that can impact the functionality and performance of the product. Therefore, to get an insight into this testing, mentioned below are some of its features:

  • It requires complete knowledge of the program’s structure.
  • Path testing is often used by software programmers to unit test the code of the software product.
  • It is a white box testing technique.
  • Helps in evaluating the internal flow of the software product.
  • Effective for exploring large quantity of defects during unit testing.
  • It calculates the number of tests to be executed based on the cyclomatic complexity and generates separate test cases for each path to be executed.
  • It covers all the paths under the test. However, it does not identify all the defects, as there are many defects, which may arise due to certain reasons, such as:
    • Path followed by the process is not in order, which may result in an error in the software application. For example, a process is required to be executed, and the path to be followed by it should A→B→C. But it takes the wrong path i.e. A→C→B.
    • Mistakes introduced by the developer in the source code, such as inadvertently, forgotten to add processing in the code(s), which may lead to no path, in the direction of executing the code.

Assumptions Made Before Path Testing:

Before moving on to the process of path testing, it is vital for us to consider the various assumptions made before executing it. These assumptions are:

  • All the specifications are correct.
  • Data stored in the application is properly organized, well defined and is easily accessible
  • The absence of issues or defects other than those associated with the path.

After considering the given assumptions, the testing is carried out further through following approaches.

Path Testing Techniques:

Path testing is further categorized into three important techniques, each of which caters to a different aspect of the product and ensure its accuracy. From the testing workflow to its execution, these techniques play a critical role in the whole process and are hence defined in detail below:

  1. Control Flow Chart:
  2. Generally it involves the activity of representing the workflow of the process or program in the form of control chart or graph, which consists of nodes, links, edges, regions, etc. During this process, the flow graph or chart is constructed by the team by replacing the program control statements with equivalent diagrams.

  3. Decision to Decision (DD) Path:
  4. This strategy involves selection of one, between the two decisions, for the purpose of path's execution. It is carried out with the help of the control flow chart and includes node, which inherits one of the following traits.

    • Single node of in-degree=0 i.e. initial node.
    • Single node of out-degree=0 i.e. terminal node
    • Single node with in-degree and out-degree=1.
    • Single node with in-degree or out-degree > 2

    Further, the maximum chain length in DD path > 1

  5. Independent or Basis Path Testing:
  6. It is a widely used testing method that guarantees the complete branch coverage in the control flow graph.

    • It involves the study and analysis of the control flow graph, which contributes towards the identification of the linearly independent paths. Thereafter, these identified paths are used to design and build test cases.
    • Moreover, it includes conditional statements that are executed by the team depending on what conditions it suffices.
    • Basis testing, in short, is used to maximize test coverage and to reduce the number of redundant tests.

Advantages of Path Testing:

Similar to the miscellaneous software testing techniques, path testing also offers various advantages to the team of testers. Defining the flow of control from the starting point of the testing to its end, this testing is among the oldest types of structural testing, that offers the following advantages:

  • Path testing is mainly focused on the program logic.
  • Allows the team to analyze the flow of the program during the process of testing.
  • It is highly dependent on the source code of the program.
  • Ensures the execution of the each and every path, present in the software program, at least once.
  • A structured type of testing technique that uses control flow graph and is independent of the specifications.

Disadvantages of Path Testing:

Thought the list of benefits offered by path testing is non-exhaustive, it is crucial for us to mention the few disadvantages/drawbacks offered by this testing to help you get a thorough insight into its process and features. These disadvantages are:

  • Presence of defects cannot be traced out by the path testing due to an error in the specifications.
  • Path testing requires expert and skillful testers, with in-depth knowledge of programming and code.
  • It is difficult to test all paths with this type of testing technique when the product becomes more complex.


There are several testing techniques like data flow and equivalence class testing that are performed by the team during STLC. However, path testing is implemented by them to identify various issues in the code, which can become a hindrance in testing. This testing, which is extensively effective during unit testing, helps improve the process of testing as well as the quality and functionality of the product.