Can unit tests replace “testing”?


Unit testing includes testing of individual components that can validate as per the design tests. It allows you to organize tests by code.

What are unit tests and who designs them obviously the developers? The small testable parts of the program make it easy to identify and rectify the errors.

Unit test is not an option to complete testing as unit tests can lead to detailed and accurate testing. Trace out the defects at an early stage preventing huge loss time money and efforts.

Why did the need for unit tests crop up when complete testing was a practice?

  • The end to end development and delivery to market needed improvement
  • Testing whole software requires more time and efforts
  • Bug fixing at a later stage made re-programming difficult
  • Identifying coding defects was not possible yet affected the functionality
  • Design clarity was missing and compromised
  • Quality check of the build is possible done towards the end of the development cycle
  • No code review added to quality concerns
  • Changing the code laid severe repercussions
  • The illusion that everything should be tested in one shot broke when unit tests were introduced

Challenges in creating unit tests:

  • Coding knowledge is compulsory to write tests
  • To be executed by developers
  • Each piece of the application should be functional
  • Update and create new tests requires the involvement of developers
  • Tests should ultimately improve on the improvement of the development process
  • All codes should be unit tested to draw benefits
  • Coverage of 100% testing in a unit test is a myth
  • Clarity on what and how should it be tested is must

Benefits of unit tests:

  • Unit test let’s you maintain the quality of codes
  • It makes codes reusable and speeds up development 
  • Controls recurring efforts and costs of fixing the defects
  • No need to prepare test cases for everything instead; you can focus on unit test
  • It brings in clarity to trace the real reason of the error
unit tests

What and how to test?

Overall, we need to define what and what not to test in a unit test. Prepare unit test plan review it and work on it with the unit test cases and scripts. We require the codes to be independent of each other to build good unit test.

Testing something that does not include logic in a unit test is unnecessary. Set the rules for unit test according to the needs of organization and projects.

It can be effective if we use production data for the test. Where data is authentic and is not required, you can exclude the check. Otherwise checking the basic level validations can be included.

 Usually, unit test does not interact with the database but if the project demands, include that. Optionally inject an independent repository for the mock test.

Object in all layers essentially requires verification even if the field can be null. Include acceptable data in the field that has validations attached to it.

Unit tests are robust and if compilation errors exist, it lets you deal with it. This can save you from complex deployment scripts and the time consumed in the feedback cycle.

Unit tests save you from the failure of projects in long run. The balance required in overall testing is achievable by taking into consideration all different components of the program. Include everything and anything that is important to run a program accurately.

Comparison between Unit tests and Testing:

Unit TestsTesting
Easy to create and runNo concern with coding as the objective is functional testing
Fast and helps writing clean codesSlow and complex due to size of activity
Ideal time to write your tests is when you are writing codesIdeal time to create testing document is when your requirement is freezed, and feature is designed
Separate testing of Service Layer, Domain and DatabaseIntegrated testing of Service Layer, Domain and Database
Build test for even minor checksIt is done on a large scale involving more points
Check the complex applications by breaking them to small manageable testsTest complex applications as a whole
Does not consider user requirementsFocuses on user requirements
Writing and execution is easyComplicated in comparison to the unit tests
Covers individual modules/unitsCovers entire application’s functionality
Low costs and maintenanceHigh costs and maintenance
Tests covers fixed number of lines of codeIt includes the number of requirements
Frequent changes required in tests and codingInfrequent changes required in tests and coding
Not full proof as developers write themInvolves many things as testers write it
Number of test cases is higher so automation is mustLower test cases compared to unit tests hence both Manual and automation testing can be opted
Helps improve software qualityHelps improve features
Reports can include components taken into consideration, its expected behavior, & expected versus actual resultReports can include features taken into consideration, its expected performance, & expected versus actual output
If unit tests are written poorly it fails the purpose, especially when the designs are not clear It can establish a relation between unit tests and functionality testing 
Unit tests are written before productionFinalized after features have been developed
Tests may not function properly when codes are changed, but if the same code is already covered in the tests, the developers can work on itThere is no dependency on codes at all
Helps set boundaries and predict mistakesIt does not give a chance for predictability
Testing of codesTesting of functions
It is no replacement to functional testingUnit tests are the reliable checkpoints, using both has a straight impact on quality of software

Can unit tests replace “testing”?

Quite impractical, as software testing is a combination and series of various processes formed with an intention to crosscheck the accurate functioning of the codes. For developers, finding flaws with their coding is like pointing fingers to themselves. If we cultivate this habit of appreciating testers, it will encourage an eye for detail. The more detailed checking of testing leads to a higher probability of high-quality programs.

In smaller projects, one may get a feel of unit tests replacing testing, which is because of lesser check needed.

In general, developers opine to have written perfectly crafted codes. Proof-reading tends to assist in healthier practices of development. “Be a yardstick of quality. Some people aren’t used to an environment where excellence is expected.”— Steve Jobs   

Testing breaks the illusion that things are fine, but at the same time, it is an opening for finding some new bugs. Bugs are neither creation of testing nor are the end-result of coding; it’s representation of factual data.

Conceptually conceived product when passes through unit tests; the efforts are concentrated. The smaller lots of test loads reduce investable time and efforts. Wrought the testing but let it flow through a definite testing plan so that you can deliver to meet market challenges.

Testing mindset can figure out the loopholes and developers can fix them.


A unit test clears the blockage and avoids bottlenecks by eliminating the impurities within code in a very primitive stage. Everything is correct until; not proven incorrect. The “moment of truth” entangled with ample of bugs wobbling your head is horrifying. There is no foolproof test management system, so deal with it gradually; it allows you to discover ways to treat the chaos. Automation provides unbiased reports; hence, I recommend methodological testing.


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