cypress-upload-file-post-form/cypress/integration/upload_file_to_form_spec.js

Solution for two Cypress testing use-cases I came across with: perform a direct http FORM request to the server containing a file and other parameters and upload a file into a form before submission

// Upload an excel file, fill in other inputs and submit the form

describe('Testing the excel form', function () {
  it ('Uploading the right file imports data from the excel successfully', function() {

      const testUrl = 'http://localhost:3000/excel_form';
      const fileName = 'your_file_name.xlsx';
      const fileType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
      const fileInput = 'input[type=file]';

      cy.visit(testUrl);
      cy.upload_file(fileName, fileType, fileInput);
      cy.get('#other_form_input2').type('input_content2');

      cy.get('button').contains('Submit').click();

      cy.get('.result-dialog').should('contain', 'X elements from the excel where successfully imported');
  })
})