rocketchat_1          | RESULT :{"profile":{"inResponseToId":{"name":"InResponseTo","value":"id-zxQqTspXesiZZN3ss","prefix":"","local":"InResponseTo","uri":""},"issuer":"https://sso.domain.com/simplesaml/saml2/idp/metadata.php","nameID":"_5a7f2da50d48a53fbc9887f73a92b223d022a4a652","nameIDFormat":{"name":"Format","value":"urn:oasis:names:tc:SAML:2.0:nameid-format:transient","prefix":"","local":"Format","uri":""},"sessionIndex":{"name":"SessionIndex","value":"_f136784399ecc621ace66752e2fb9909f214d50c0e","prefix":"","local":"SessionIndex","uri":""},"memberOf":"cn=company,ou=company,dc=domain,dc=com","entryDN":"cn=username,ou=people,dc=domain,dc=com","groups":"anothergroup","urn:oid:2-5-4-3":"username","urn:oid:2-5-4-4":"name","urn:oid:2-16-840-1-113730-3-1-241":"My name","urn:oid:2-5-4-42":"My","urn:oid:0-9-2342-19200300-100-1-3":"[email protected]","urn:oid:0-9-2342-19200300-100-1-1":"username"}}
rocketchat_1          | Exception while invoking method 'login' Error: SAML Profile did not contain an email address

$metadata['https://{{ simplesaml_rocketchat_domain}}/_saml/metadata/rocketchat'] = array (
  'entityid' => 'https://{{ simplesaml_rocketchat_domain}}/_saml/metadata/rocketchat',
  'contacts' => 
  array (
  ),
  'metadata-set' => 'saml20-sp-remote',
  'AssertionConsumerService' => 
  array (
    0 => 
    array (
      'Binding' => 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
      'Location' => 'https://{{ simplesaml_rocketchat_domain}}/_saml/validate/rocketchat',
      'index' => 1,
      'isDefault' => true,
    ),
  ),
  'SingleLogoutService' => 
  array (
    0 => 
    array (
      'Binding' => 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect',
      'Location' => 'https://{{ simplesaml_rocketchat_domain}}/_saml/logout/rocketchat/',
      'ResponseLocation' => 'https://{{ simplesaml_rocketchat_domain}}/_saml/logout/rocketchat/',
    ),
  ),
  'NameIDFormat' => 'urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress',
  'keys' => 
  array (
    0 => 
    array (
      'encryption' => true,
      'signing' => true,
      'type' => 'X509Certificate',
      'X509Certificate' =>'[removed]',
    ),
  ),
);

<?php
$metadata['__DYNAMIC:1__'] = array(
    /*
     * The hostname for this IdP. This makes it possible to run multiple
     * IdPs from the same configuration. '__DEFAULT__' means that this one
     * should be used by default.
     */
    'host' => '__DEFAULT__',

    /*
     * The private key and certificate to use when signing responses.
     * These are stored in the cert-directory.
     */
    'privatekey' => 'domain.com.pem',
    'certificate' => 'comain.com.crt',

    /*
     * The authentication source which should be used to authenticate the
     * user. This must match one of the entries in config/authsources.php.
     */
    'auth' => 'ldap',
    'attributes.NameFormat' => 'urn:oasis:names:tc:SAML:2.0:attrname-format:uri',
    'signature.algorithm' => 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha256',
    
    'authproc' => array(
         50 => array(
         
             'class' => 'ldap:AttributeAddUsersGroups',
             'ldap.basedn' => 'dc=domain,dc=com',
             'ldap.product' => 'OpenLDAP',

             'authsource' => 'ldap',
             'attribute.dn' => 'entryDN',
             'attribute.username' => 'entryDN',
             
             'attribute.member' => 'cn',
             'attribute.memberof' => 'uniqueMember',
             
           'ldap.username' => '{{ simplesaml_ldap_serviceaccount }}',
           'ldap.password' => '{{ simplesaml_ldap_servicepassword }}',

         ), 
        // Convert LDAP names to oids.
        100 => array('class' => 'core:AttributeMap', 'name2oid'), #  <-- This line changes  SAML key ``mail`` to   ``oid:0.9.2342.19200300.100.1.3``. Removing this line fixes rocket.chat (but breaks other SAML configured services for my company)
    ),
);

--

I hope above may help in setting up SAML testcases for rocketchat