ETL Testing: Definition , Importance , Types and Tools

Types of ETL Testing

below are the main types of testing that are covered under ETL testing:

1) Constraint Testing:

The tester identifies whether the data is mapped from source to target or not. Below are some validation points

• • NOT NULL
  • Default
  • Check
  • UNIQUE
  • Foreign key
  • Primary Key

2) Source to Target Count Testing:

Data should be matched from source to Target and count should be same.

3) Source to Target Data Validation Testing:

Tester validates the each and every point of the source to target data.

4) Duplicate Check Testing:

• • In this phase of ETL Testing, there should not be any duplicate values for unique columns.
  • Duplicate data can arise due to many reason For example missing primary key, data Transformation from source to target etc.
  • Duplicate values can be checked with SQL statement like −

Select studentID, studentName, Quantity, COUNT (*)
FROM Student
GROUP BY studentID, studentName, Quantity HAVING COUNT (*) >1;

5) Data Integration Testing: 

It makes sure that the data from different sources has been loaded properly into the target system and all the threshold values are checked.

6) Application Migration Testing: 

This testing ensures that the ETL application is working fine on moving to a new platform.

7) Incremental and Historical Process Testing:

In the Incremental data, the historical data should not be corrupted.   When it is corrupted then Bugs has been raised.

8) Navigation Testing:

Navigation Testing is the End user point of view testing. An end user cannot follow the friendly of the application that navigation is called as bad or poor Navigation. At the time of Testing, A tester can identify this type of navigation scenarios to avoid unnecessary navigation.

9) Transformation Testing:

During transformation of data from Source to Target , Data Mapping has been checked.

10) Regression Testing:

Re-running tests to ensure that previously developed and tested software still performs after a change.

11) Retesting:

It is a process re-execution of the failed test cases after fixing the bug.

12) End-to-end testing

End-to-end testing, also called data integration testing, is used to find out how data fits beyond the ETL pipeline.