Code Coverage vs Test Coverage

Code Coverage vs Test Coverage

Software tests are done to check whether the software developed comes out like it was supposed to. Out of the hundreds of software techniques out there, code and test coverage are the surest ways to measure code quality.

In this piece, you’ll learn the relevance of these two testing techniques and understand their key differences. i.e Code coverage vs test coverage

What Is Code Coverage In Unit Testing?

Code coverage metrics show the degree to which any software or application code has been Tested. A large number of unit test cases are run on the application code to understand the code quality. This is an example of white-box software testing.

In some cases, several test cases are further included to boost the code coverage. This is usually done when the software or application is running. Coverage reports tell developers about the number of line codes or branches that have been tested. In simple words, it provides a quantitative measure of the code that’s been left untouched and executed.

How Do I Check My Code Coverage?

To calculate the percentage of code coverage, divide the number of code lines executed by a test by the total number of lines in a system component. Multiply what you get by 100.

Lines of code and branches that have been exercised by running test cases are measured by considering various criteria.

These include:

  • Function Coverage – A measure of the functions in a source code that has been called and executed.
  • Line Coverage– This represents the number of lines coverage at run time.
  • Statement Coverage – This represents the total number of validated statements in a source code.
  • Decision/Branch Coverage – Loops of decision control structures that have been executed well.
  • Condition Coverage – Validated Boolean expressions that have been executed as true or false during the test runs.

What should I Exclude From Code Coverage?

Almost all applications contain classes that we don’t want to test. Typical candidates to this are Data Transfer Objects (DTO) and primitive models.

An easy way to omit code from coverage analysis is to utilize your coverage tool’s relevant exclusion attribute or fail to include specific metrics in your tests.

How Do You Generate a Coverage Report?

RKTracer provides all code coverage levels for C, C++, Objective C, Java, Kotlin, JavaScript, C-share, Python, Golang, and Swift programming languages. Reports are generated in HTML and XML formats and can be published in Jenkins and SonarQube.

 Useful resources on how to generate code coverage reports:

RKTracer's useful links

What Is Test Coverage In Testing?

Test coverage is a technique that determines if test cases are covering the software code. It also measures how much code is exercised when those test cases are run.

Let’s assume a case where there are 10 requirements with 100 test cases created. Supposing 90 cases are executed, that would result in a 90% test coverage. Based on this metric, you can make additional test cases for the pending tests.

Test coverage will help you identify gaps at an early level of the code. As a result, you can prioritize test suite minimization and augmentation.

What is the Proper Test Coverage?

In test coverage, there’s no one-size-fits-all guide. However, you should concentrate your time and resources in the most efficient ways by using the right test coverage metrics. These are metrics that measure and monitor any testing activity.

To know whether you’re on the right path as far as test metrics are concerned, ask yourself these questions:

  1. How much of your software was tested?
  2. Are there bugs that you didn’t find during tests?
  3. How much longer will it take to test?
  4. Am I testing against the right platforms or environments?

Test Coverage Techniques – How To Measure Unit Test Coverage

To measure unit test coverage, use this formula.

Divide the number of lines in all your code test cases and divide it by the total number of code lines in your software

For example, if your total number of code in your system is 1,000 and the lines executed in a test were 700, your test coverage would be 70%

Code Coverage= 700/1,000 *100=70%

How do You Get 100% Test Coverage?

Tests should cover much of your code, preferably 100%. Any part of your code that’s left untested can be changed by other developers at any time, potentially causing a break of the functionality remaining unnoticed.

Test coverage is measured in several ways, including line, branch, and function coverage, and so on. 

Always ensure that you have covered the essential assertions related to your application’s functionality while writing tests.

All the same, don’t spend too much time trying to hit 100% test coverage. The generally accepted or sufficient coverage is 80%.

Code Coverage vs Test Coverage — Which Is Better?

 

Code coverage and test coverage are measured on a different basis. While code coverage is measured by the features covered during tests, test coverage is calculated using tests.

So what is best suited for software projects?

There’s no definite answer to this. The right solution depends on the complexity and type of project. In many cases, code and test coverage are used because they are equally useful in development projects.

Benefits of Code Coverage

  1. Code coverage indicates the effectiveness of a test code and offers suggestions on how to increase the coverage.
  2. You can use open-source and premium tools to test code coverage and get results. Setting up either of these coverage tools does not take much time.
  3. Code coverage helps improve the quality of code by capturing uncovered code and help one to improve testing efficiency.

Drawbacks of Code Coverage

  1. Most code coverage tools (mostly open-source) only work when we have unit tests.
  2. The methodology used by code coverage tools could be different. Therefore, you may be unable to compare the code coverage results of a tool to another.
  3. Finding the best tool for code coverage can be a big task. You’ll have to compare and try out different features from as many tools before choosing one that best suits your project requirements.
  4. Many code coverage tools do not provide support for different programming languages. For example, a tool that supports the Java Programming language could not be supporting Python, C, Go, and so on.

Benefits of Test Coverage

  1. It is an excellent approach to test software features. You can compare the results you get across different specification documents. This could include the product, features, requirements, UI/UX, and so on.
  2. Test coverage is a black-box testing technique. Therefore, executing test coverage tests will not need much expertise.

Drawbacks of Test Coverage

  1. Test coverage doesn’t offer a scope of automation. This is because tests are usually black-box. Hence, you will have to make manual test results comparisons with an expected output. This is simply because tests are done at a “feature level” instead of a “code level.”
  2. There isn’t a concrete way to measure test coverage. Therefore, coverage results are highly dependent on the domain competence of the person doing the tests. This varies from one tester to the other.

Code Coverage vs Functional Coverage

Functional coverage is a measure of the functionality of a design in a test. It calls for the development of a functionality list to be checked and data collection to show the functionality of a concern that’s being assessed.

The user defines coverage points for the functions to be covered and is entirely under the user’s control.

Like code coverage, 100% functional coverage would mean that all the test plan items are tested. When this is combined with a high code coverage percentage, the implication would be that testing is well done.

How Much Coverage Is Enough?

No thumb rule mentions the minimum code coverage percentage. Neither is there one for test coverage.

But you can make the most out of this.

If you do more tests, you’ll get a better end product. It would help if you frequently communicated with design, development, and test teams to keep each stakeholder informed about the project’s activities.

Spend a reasonable time understanding the project’s overall requirements and make the test activities a priority. To be on track with the progress, get everyone in the team a checklist that’s updated periodically or after every release.

It is necessary for the test team to communicate frequently with the Quality Assurance team. Your QA team will most probably have details about the target coverage that needs to be achieved for a software to be released to the end-user.

What is a Good Percentage of Test Code Coverage?

Code coverage is an important metric. However, its scope is limited. This means that there isn’t an ideal way to measure the effectiveness of those efforts you spent on testing. This makes 100% coverage only a myth.

A 100% code coverage indicates that all code lines are covered through the automated test scripts you have. However, there’s a need to consider false negatives and positives, most of which don’t include added code. In short, there could be some of the codes in a web application that could be untested.

Maximize Your Coverage Through Proper Planning 

One way to achieve great results through testing is by incorporating automation in your test plan. Since not all testing process can’t be automated(except uni testing), you can only create a plan.

Your plan should highlight test activities that need to be performed via automation and manually.

An approach encompassing different tests like integration testing, automation testing, cross-browser testing, manual testing, etc., can help. It’ll enable you to measure the efficiency of other test systems and tests in a single place.

Just don’t aim for 100% code coverage.

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