Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.407
diff -u -p -r1.407 form.inc
--- includes/form.inc	27 Nov 2009 15:14:58 -0000	1.407
+++ includes/form.inc	28 Nov 2009 16:19:22 -0000
@@ -459,6 +459,10 @@ function drupal_form_submit($form_id, &$
   // Merge in default values.
   $form_state += form_state_defaults();
 
+  // Reset form validation.
+  $form_state['must_validate'] = TRUE;
+  form_clear_error();
+
   drupal_prepare_form($form_id, $form, $form_state);
   drupal_process_form($form_id, $form, $form_state);
 }
Index: modules/simpletest/tests/form.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/form.test,v
retrieving revision 1.25
diff -u -p -r1.25 form.test
--- modules/simpletest/tests/form.test	18 Nov 2009 18:51:11 -0000	1.25
+++ modules/simpletest/tests/form.test	28 Nov 2009 16:42:34 -0000
@@ -354,6 +354,71 @@ class FormsElementsTableSelectFunctional
 }
 
 /**
+ * Test the programmatic form submission behavior.
+ */
+class FormsProgrammaticTestCase extends DrupalWebTestCase {
+
+  function getInfo() {
+    return array(
+      'name' => 'Programmatic form submissions',
+      'description' => 'Test the programmatic form submission behavior.',
+      'group' => 'Form API',
+    );
+  }
+
+  function setUp() {
+    parent::setUp('form_test');
+  }
+
+  /**
+   * Test the programmatic form submission workflow.
+   */
+  function testSubmissionWorkflow() {
+    // Backup the current batch status and reset it to avoid conflicts while
+    // processing the dummy form submit handler.
+    $current_batch = $batch =& batch_get();
+    $batch = array();
+
+    $this->submitForm();
+    $this->submitForm('test 1');
+    $this->submitForm();
+    $this->submitForm('test 2');
+
+    // Restore the current batch status.
+    $batch = $current_batch;
+  }
+
+  /**
+   * Helper function used to programmatically submit the form defined in
+   * form_test.module with the given value.
+   *
+   * @param string $value
+   *   The field value to be submitted.
+   */
+  private function submitForm($value = NULL) {
+    // Programmatically submit the given value.
+    $form_state = array('values' => array('submitted_field' => $value));
+    drupal_form_submit('form_test_programmatic_form', $form_state);
+
+    $errors = form_get_errors();
+    $valid_form = empty($errors);
+    $valid_input = !empty($value);
+
+    // If no value was passed the form should return an error and viceversa.
+    $args = array('%value' => $value, '%errors' => $valid_form ? '' : implode(' ', $errors));
+    $this->assertTrue($valid_input == $valid_form, t('Input value: %value<br/>Validation handler errors: %errors', $args));
+
+    // We check submitted values only if we have a valid input.
+    if ($valid_input) {
+      // By fetching the value from $form_state['storage'] we ensure that the
+      // submission handler was properly executed.
+      $submitted_value = $form_state['storage']['programmatic_form_submit'];
+      $this->assertTrue($submitted_value == $value, t('Submission handler correctly executed: %submitted_value', array('%submitted_value' => $submitted_value)));
+    }
+  }
+}
+
+/**
  * Test using drupal_form_submit in a batch.
  */
 class FormAPITestCase extends DrupalWebTestCase {
Index: modules/simpletest/tests/form_test.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/form_test.module,v
retrieving revision 1.17
diff -u -p -r1.17 form_test.module
--- modules/simpletest/tests/form_test.module	21 Nov 2009 17:01:31 -0000	1.17
+++ modules/simpletest/tests/form_test.module	28 Nov 2009 16:42:46 -0000
@@ -212,6 +212,40 @@ function _form_test_tableselect_js_selec
 }
 
 /**
+ * Form builder to test programmatic form submissions.
+ */
+function form_test_programmatic_form($form, &$form_state) {
+  $form['submitted_field'] = array(
+    '#title' => 'Submitted',
+    '#type' => 'textfield',
+  );
+
+  return $form;
+}
+
+/**
+ * Form validation handler for programmatic form submissions.
+ *
+ * To test that the validation handler is correctly executed, the field value is
+ * explicitly required here.
+ */
+function form_test_programmatic_form_validate($form, &$form_state) {
+  if (empty($form_state['values']['submitted_field'])) {
+    form_set_error('submitted_field', t('Submitted field is required.'));
+  }
+}
+
+/**
+ * Form submit handler for programmatic form submissions.
+ *
+ * To test that the submission handler is correctly executed, we store the
+ * submitted value in a place we can access from the caller context.
+ */
+function form_test_programmatic_form_submit($form, &$form_state) {
+  $form_state['storage']['programmatic_form_submit'] = $form_state['values']['submitted_field'];
+}
+
+/**
  * Page callback for the batch/drupal_form_submit interaction test.
  *
  * When called without any arguments we set up a batch that calls