diff --git a/_tests_/main.test.ts b/_tests_/main.test.ts
new file mode 100644
index 00000000..4e44284c
--- /dev/null
+++ b/_tests_/main.test.ts
@@ -0,0 +1,330 @@
+import { main } from '../src/main'
+import { PipelineRunner } from '../src/pipeline.runner';
+import { TaskParameters } from '../src/task.parameters';
+import { PipelineHelper } from '../src/util/pipeline.helper';
+import { UrlParser } from '../src/util/url.parser'
+import * as core from '@actions/core';
+import { PipelineNotFoundError } from '../src/pipeline.error';
+
+var mockQueueBuildResult;
+const mockQueueBuild = jest.fn().mockImplementation(() => {
+    return mockQueueBuildResult;
+});
+
+var mockBuildDefinition;
+const mockGetDefinition = jest.fn().mockImplementation(() => {
+    return mockBuildDefinition;
+});
+
+var mockBuildDefinitions;
+const mockGetDefinitions = jest.fn().mockImplementation(() => {
+    return mockBuildDefinitions;
+});
+
+const mockGetBuildApi = jest.fn().mockImplementation(() => {
+    return {
+        getDefinitions: (projectName, pipelineName) => mockGetDefinitions(projectName, pipelineName),
+        getDefinition: (projectId, buildId) => mockGetDefinition(projectId, buildId),
+        queueBuild: (build, projectId, ignoreWarnings) => mockQueueBuild(build, projectId, ignoreWarnings)
+    }
+});
+
+const mockGetPersonalAccessTokenHandler = jest.fn().mockImplementation();
+
+var mockReleaseDefinitions;
+const mockGetReleaseDefinitions = jest.fn().mockImplementation(() => {
+    return mockReleaseDefinitions;
+});
+
+var mockReleaseResponse;
+const mockCreateRelease = jest.fn().mockImplementation(() => {
+    return mockReleaseResponse;
+});
+
+const mockGetReleaseApi = jest.fn().mockImplementation(() => {
+    return {
+        getReleaseDefinitions: (project, searchText, artifactType) => mockGetReleaseDefinitions(project, searchText, artifactType),
+        createRelease: (releaseStartMetadata, project) => mockCreateRelease(releaseStartMetadata, project)
+    }
+});
+
+jest.mock('azure-devops-node-api', () => {
+    return {
+        getPersonalAccessTokenHandler: (token) => mockGetPersonalAccessTokenHandler(token),
+        WebApi: jest.fn().mockImplementation(() => {
+            return {
+                getBuildApi: async (url, handler) => await mockGetBuildApi(url, handler),
+                getReleaseApi: async () => await mockGetReleaseApi(),
+            }
+        }) 
+    }
+});
+
+describe('Testing all functions of class PipelineHelper', () => {
+    test('EnsureValidPipeline() - throw error if definition not found', () => {
+        expect(() => PipelineHelper.EnsureValidPipeline('someProject', 'somePipeline', [])).toThrow(new PipelineNotFoundError(`Pipeline named "${'somePipeline'}" not found in project "${'someProject'}"`));
+    });
+
+    test('EnsureValidPipeline() - throw error if more than one definition found', () => {
+        expect(() => PipelineHelper.EnsureValidPipeline('someProject', 'somePipeline', [{}, {}])).toThrow(`More than 1 Pipeline named "${'somePipeline'}" found in project "${'someProject'}"`);
+    });
+
+    test('equals() - return if strings are equal', () => {
+        expect(PipelineHelper.equals(null, null)).toBeTruthy();
+        expect(PipelineHelper.equals('a', null)).toBeFalsy();
+        expect(PipelineHelper.equals(null, 'a')).toBeFalsy();
+        expect(PipelineHelper.equals('a', 'a ')).toBeTruthy();
+        expect(PipelineHelper.equals('a', 'A')).toBeTruthy();
+        expect(PipelineHelper.equals('a', 'b')).toBeFalsy();
+    });
+
+    test('processEnv() - return specified env variable', () => {
+        process.env['envVar'] = 'value';
+        expect(PipelineHelper.processEnv('envVar')).toBe('value');
+    });
+
+    test('processEnv() - throw error if specified envVar is not available', () => {
+        process.env['envVar'] = '';
+        expect(() => PipelineHelper.processEnv('envVar')).toThrow(`env.${'envVar'} is not set`);
+    });
+
+    test('isGitHubArtifact() - returns if artifact if of type github', () => {
+        expect(PipelineHelper.isGitHubArtifact({})).toBeFalsy();
+        expect(PipelineHelper.isGitHubArtifact({ type: 'githuB' })).toBeTruthy();
+        expect(PipelineHelper.isGitHubArtifact({ type: null })).toBeFalsy();
+    });
+
+    test('getErrorAndWarningMessageFromBuildResult() - concatenate and return errors', () => {
+        expect(PipelineHelper.getErrorAndWarningMessageFromBuildResult([
+            { message: 'FirstMessage', result: 2},
+            { message: 'FirstIgnoredMessage', result: 0},
+            { message: 'SecondIgnoredMessage', result: 1},
+            { message: 'SecondMessage', result: 2},
+        ])).toMatchObject({
+            errorMessage: 'FirstMessage,SecondMessage',
+            warningMessage: '',
+        });
+    });
+
+    test('getErrorAndWarningMessageFromBuildResult() - concatenate and return warnings if no errors', () => {
+        expect(PipelineHelper.getErrorAndWarningMessageFromBuildResult([
+            { message: 'FirstIgnoredMessage', result: 0},
+            { message: 'SecondIgnoredMessage', result: 1},
+        ])).toMatchObject({
+            errorMessage: '',
+            warningMessage: 'FirstIgnoredMessage,SecondIgnoredMessage',
+        });
+    });
+
+    test('getErrorAndWarningMessageFromBuildResult() - message validation error which do not come in form of array', () => {
+        expect(PipelineHelper.getErrorAndWarningMessageFromBuildResult(
+            { message: 'ErrorMessage' } as any
+        )).toMatchObject({
+            errorMessage: 'ErrorMessage',
+            warningMessage: '',
+        });
+    });
+
+    test('getErrorAndWarningMessageFromBuildResult() - message from server error which do not come in form of array', () => {
+        expect(PipelineHelper.getErrorAndWarningMessageFromBuildResult(
+            { serverError: { message: 'ServerErrorMessage'  } } as any
+        )).toMatchObject({
+            errorMessage: 'ServerErrorMessage',
+            warningMessage: '',
+        });
+    });
+});
+
+describe('Testing all functions of class UrlParser', () => {
+    test('GetProjectName() - return project name from project URL', () => {
+        expect(UrlParser.GetProjectName('https://dev.azure.com/organization/project-name ')).toBe('project-name');
+    });
+
+    test('GetProjectName() - throw error if null or empty', () => {
+        expect(() => UrlParser.GetProjectName(null)).toThrow('Project url is null or empty. Specify the valid project url and try again');
+        expect(() => UrlParser.GetProjectName('')).toThrow('Project url is null or empty. Specify the valid project url and try again');
+    });
+
+    test('GetProjectName() - throw error if invalid url', () => {
+        expect(() => UrlParser.GetProjectName('https://dev.azure.com/organization/project-name/')).toThrow(`Failed to parse project url: "${'https://dev.azure.com/organization/project-name/'}". Specify the valid project url (eg, https://dev.azure.com/organization/project-name or https://server.example.com:8080/tfs/DefaultCollection/project-name)) and try again.`);
+        expect(() => UrlParser.GetProjectName('https://dev.azure.com/organization//')).toThrow(`Failed to parse project url: "${'https://dev.azure.com/organization//'}". Specify the valid project url (eg, https://dev.azure.com/organization/project-name or https://server.example.com:8080/tfs/DefaultCollection/project-name)) and try again.`);
+    });
+
+    test('GetCollectionUrlBase() - return collections base URL', () => {
+        expect(UrlParser.GetCollectionUrlBase('https://dev.azure.com/organization/project-name ')).toBe('https://dev.azure.com/organization');
+    });
+
+    test('GetCollectionUrlBase() - throw error if null or empty', () => {
+        expect(() => UrlParser.GetCollectionUrlBase(null)).toThrow('Project url is null or empty. Specify the valid project url and try again');
+        expect(() => UrlParser.GetCollectionUrlBase('')).toThrow('Project url is null or empty. Specify the valid project url and try again');
+    });
+
+    test('GetCollectionUrlBase() - throw error if invalid url', () => {
+        expect(() =>  UrlParser.GetCollectionUrlBase('/')).toThrow(`Failed to parse project url: "${'/'}". Specify the valid project url (eg, https://dev.azure.com/organization/project-name or https://server.example.com:8080/tfs/DefaultCollection/project-name)) and try again.`);
+    });
+});
+
+describe('Testing all functions of class PipelineRunner', () => {
+    test('start() - regular run using env variables and inputs to trigger a run', async () => {
+        jest.spyOn(core, 'getInput').mockImplementation((input, options) => {
+            process.env['GITHUB_REPOSITORY'] = 'repo_name';
+            process.env['GITHUB_REF'] = 'releases';
+            process.env['GITHUB_SHA'] = 'sampleSha';
+
+            if (input == 'azure-devops-project-url') return 'https://dev.azure.com/organization/my-project';
+            if (input == 'azure-pipeline-name') return 'my-pipeline';
+            if (input == 'azure-devops-token') return 'my-token';
+        });
+        jest.spyOn(core, 'debug').mockImplementation();
+        jest.spyOn(core, 'info').mockImplementation();
+        mockBuildDefinitions = [{
+            id: 5
+        }];
+        mockBuildDefinition = {
+            id: 5,
+            repository: {
+                id: 'repo',
+                type: 'Devops'
+            },
+            project: {
+                id: 'my-project'
+            },
+        }
+        mockQueueBuildResult = {
+            _links: {
+                web: {
+                    href: 'linkToRun'
+                }
+            }
+        };
+
+        expect(await (new PipelineRunner(TaskParameters.getTaskParams())).start()).toBeUndefined();
+        expect(mockGetPersonalAccessTokenHandler).toBeCalledWith('my-token');
+        expect(mockGetBuildApi).toBeCalled();
+        expect(mockGetDefinitions).toBeCalledWith('my-project', 'my-pipeline');
+        expect(mockGetDefinition).toBeCalledWith('my-project', 5);
+        const expectedBuild = {
+            definition: {
+                id: 5,
+            },
+            project: {
+                id: 'my-project',
+            },
+            reason: 1967,
+            sourceBranch: null,
+            sourceVersion: null,
+        }
+        expect(mockQueueBuild).toBeCalledWith(expectedBuild, 'my-project', true);
+    });
+
+    test('start() - set core failed in RunYamlPipeline if result has errors', async () => {
+        jest.spyOn(core, 'getInput').mockImplementation((input, options) => {
+            process.env['GITHUB_REPOSITORY'] = 'repo_name';
+            process.env['GITHUB_REF'] = 'releases';
+            process.env['GITHUB_SHA'] = 'sampleSha';
+
+            if (input == 'azure-devops-project-url') return 'https://dev.azure.com/organization/my-project';
+            if (input == 'azure-pipeline-name') return 'my-pipeline';
+            if (input == 'azure-devops-token') return 'my-token';
+        });
+        jest.spyOn(core, 'debug').mockImplementation();
+        jest.spyOn(core, 'info').mockImplementation();
+        jest.spyOn(core, 'setFailed').mockImplementation();
+        mockBuildDefinitions = [{
+            id: 5
+        }];
+        mockBuildDefinition = {
+            id: 5,
+            repository: {
+                id: 'repo_name',
+                type: 'Github'
+            },
+            project: {
+                id: 'my-project'
+            },
+        }
+        mockQueueBuildResult = {
+            validationResults: [{}]
+        };
+        expect(await (new PipelineRunner(TaskParameters.getTaskParams())).start()).toBeUndefined();
+        expect(mockGetPersonalAccessTokenHandler).toBeCalledWith('my-token');
+        expect(mockGetBuildApi).toBeCalled();
+        expect(mockGetDefinitions).toBeCalledWith('my-project', 'my-pipeline');
+        expect(mockGetDefinition).toBeCalledWith('my-project', 5);
+        const expectedBuild = {
+            definition: {
+                id: 5,
+            },
+            project: {
+                id: 'my-project',
+            },
+            reason: 1967,
+            sourceBranch: 'releases',
+            sourceVersion: 'sampleSha',
+        }
+        expect(mockQueueBuild).toBeCalledWith(expectedBuild, 'my-project', true);
+        expect(core.setFailed).toBeCalled();
+    });
+
+    test('start() - set core failed in case of invalid response', async () => {
+        jest.spyOn(core, 'getInput').mockImplementation((input, options) => {
+            process.env['GITHUB_REPOSITORY'] = 'repo_name';
+            process.env['GITHUB_REF'] = 'releases';
+            process.env['GITHUB_SHA'] = 'sampleSha';
+
+            if (input == 'azure-devops-project-url') return 'https://dev.azure.com/organization/my-project';
+            if (input == 'azure-pipeline-name') return 'my-pipeline';
+            if (input == 'azure-devops-token') return 'my-token';
+        });
+        jest.spyOn(core, 'debug').mockImplementation();
+        jest.spyOn(core, 'info').mockImplementation();
+        jest.spyOn(core, 'setFailed').mockImplementation();
+        mockBuildDefinitions = [{}, {}];
+
+        expect(await (new PipelineRunner(TaskParameters.getTaskParams())).start()).toBeUndefined();
+        expect(mockGetPersonalAccessTokenHandler).toBeCalledWith('my-token');
+        expect(mockGetBuildApi).toBeCalled();
+        expect(mockGetDefinitions).toBeCalledWith('my-project', 'my-pipeline');
+        expect(core.setFailed).toBeCalled();
+    });
+
+    test('start() - trigger designer pipeline in case of PipelineNotFoundError', async () => {
+        jest.spyOn(core, 'getInput').mockImplementation((input, options) => {
+            process.env['GITHUB_REPOSITORY'] = 'repo_name';
+            process.env['GITHUB_REF'] = 'releases';
+            process.env['GITHUB_SHA'] = 'sampleSha';
+
+            if (input == 'azure-devops-project-url') return 'https://dev.azure.com/organization/my-project';
+            if (input == 'azure-pipeline-name') return 'my-pipeline';
+            if (input == 'azure-devops-token') return 'my-token';
+        });
+        jest.spyOn(core, 'debug').mockImplementation();
+        jest.spyOn(core, 'info').mockImplementation();
+        jest.spyOn(core, 'setFailed').mockImplementation();
+        mockBuildDefinitions = null;
+        mockReleaseDefinitions = [{
+            id: 5,
+            artifacts: []
+        }];
+        mockReleaseResponse = {
+            _links: {
+                web: {
+                    href: 'linkToRun'
+                }
+            }
+        }
+
+        expect(await (new PipelineRunner(TaskParameters.getTaskParams())).start()).toBeUndefined();
+        expect(mockGetPersonalAccessTokenHandler).toBeCalledWith('my-token');
+        expect(mockGetBuildApi).toBeCalled();
+        expect(mockGetDefinitions).toBeCalledWith('my-project', 'my-pipeline');
+        expect(mockGetReleaseApi).toBeCalled();
+        expect(mockGetReleaseDefinitions).toBeCalledWith('my-project', 'my-pipeline', 4);
+        const expectedRelease = {
+            artifacts: [], 
+            definitionId: 5, 
+            reason: 2
+        };
+        expect(mockCreateRelease).toBeCalledWith(expectedRelease, "my-project");
+    });
+});