I know that there is a plugin for doing this in cypress already. However using it with jar files just corrupts the file and therefore it is useless in my usecase. This is really weird because i tried it with every combination of encoding and it still does not work. Works perfectly fine with other filetypes however.
This is the code i am using (works except with jar files).
 cy.fixture('test.jar', 'binary')
            .then(Cypress.Blob.binaryStringToBlob)
            .then(fileContent => {
                cy.get('[data-cy="dropzone"]')
                    .contains('Jar file')
                    .parent()
                    .find('div')
                    .attachFile({
                        fileContent,
                        filePath: 'test.jar',
                        mimeType: 'application/java-archive',
                        encoding: 'binary',
                        lastModified: new Date().getTime(),
                        subjectType: 'drag-n-drop',
                        force: true
                    });
            });
I know that you can perform post requests in cypress. Is it possible to perfom the file upload with it after clicking the dropzone element?
 
    