A computer-implemented method of automatically generating test data for testing applications, said method comprising: receiving, by a test data generator, a plurality of test cases associated with a plurality of test scenarios of the testing applications; generating, by the test data generator, a plurality of test data scripts associated with the plurality of test cases, wherein a test data script is a statement to be executed on a data source; executing, by the test data generator, the plurality of test data scripts using a plurality of test data pre-stored in a first test data source, wherein the first test data source is a centralized data repository, and wherein the plurality of test data is selected from a group consisting of: numbers, strings, letters, text, dates, and flag required for executing the plurality of test data scripts; determining, by the test data generator, a failure of the execution of the plurality of test data scripts due to unavailability of at least one test data in the first test data source; obtaining, by the test data generator, the at least one test data from a second test data source, if the execution of the plurality of test data scripts is determined to fail, wherein the second test data source is an open data repository, and wherein the obtaining the at least one test data from the second test data source comprises: generating, using an Open Data Source - ODS-framework of the test data generator, one or more individual Application Program Interface - API-adaptors for accessing the open data repository; converting, using an Entity Data Model - EDM-in the ODS framework, the plurality of test data scripts into a query that is to-be-executed on the open data repository, upon accessing the open data repository; obtaining, using the one or more individual API adaptors, the at least one test data from the open data repository upon executing the query on the open data repository; and updating the first data source with the at least one test data obtained from execution of the query on the open data repository. receiving, by a test data generator, a plurality of test cases associated with a plurality of test scenarios of the testing applications; generating, by the test data generator, a plurality of test data scripts associated with the plurality of test cases, wherein a test data script is a statement to be executed on a data source; executing, by the test data generator, the plurality of test data scripts using a plurality of test data pre-stored in a first test data source, wherein the first test data source is a centralized data repository, and wherein the plurality of test data is selected from a group consisting of: numbers, strings, letters, text, dates, and flag required for executing the plurality of test data scripts; determining, by the test data generator, a failure of the execution of the plurality of test data scripts due to unavailability of at least one test data in the first test data source; obtaining, by the test data generator, the at least one test data from a second test data source, if the execution of the plurality of test data scripts is determined to fail, wherein the second test data source is an open data repository, and wherein the obtaining the at least one test data from the second test data source comprises: generating, using an Open Data Source - ODS-framework of the test data generator, one or more individual Application Program Interface - API-adaptors for accessing the open data repository; converting, using an Entity Data Model - EDM-in the ODS framework, the plurality of test data scripts into a query that is to-be-executed on the open data repository, upon accessing the open data repository; obtaining, using the one or more individual API adaptors, the at least one test data from the open data repository upon executing the query on the open data repository; and generating, using an Open Data Source - ODS-framework of the test data generator, one or more individual Application Program Interface - API-adaptors for accessing the open data repository; converting, using an Entity Data Model - EDM-in the ODS framework, the plurality of test data scripts into a query that is to-be-executed on the open data repository, upon accessing the open data repository; obtaining, using the one or more individual API adaptors, the at least one test data from the open data repository upon executing the query on the open data repository; and updating the first data source with the at least one test data obtained from execution of the query on the open data repository.