Enable integration tests for the crypto/ namespace (#26684)

Crypto namespace contains the openssl modules. It has no integration
testing as of now.

This commits aims to add integration tests for the crypto namespace.
This will make it easier to spot breaking changes in the future.

This tests currently apply to:

  * openssl_privatekey
  * openssl_publickey
  * openssl_csr

lib/ansible/module_utils/crypto.py

@@ -35,15 +35,12 @@ class OpenSSLObjectError(Exception):
     pass
 
 
-def get_fingerprint(path, passphrase):
+def get_fingerprint(path, passphrase=None):
     """Generate the fingerprint of the public key. """
 
     fingerprint = {}
 
-    privatekey = crypto.load_privatekey(crypto.FILETYPE_PEM,
-                                        open(path, 'rb').read(),
-                                        passphrase)
-
+    privatekey = load_privatekey(path, passphrase)
     try:
         publickey = crypto.dump_publickey(crypto.FILETYPE_ASN1, privatekey)
         for algo in hashlib.algorithms:
@@ -63,10 +60,14 @@ def load_privatekey(path, passphrase=None):
     """Load the specified OpenSSL private key."""
 
     try:
-        privatekey_content = open(path, 'rb').read()
-        privatekey = crypto.load_privatekey(crypto.FILETYPE_PEM,
-                                            privatekey_content,
-                                            passphrase)
+        if passphrase:
+            privatekey = crypto.load_privatekey(crypto.FILETYPE_PEM,
+                                                open(path, 'rb').read(),
+                                                passphrase)
+        else:
+            privatekey = crypto.load_privatekey(crypto.FILETYPE_PEM,
+                                                open(path, 'rb').read())
+
         return privatekey
     except (IOError, OSError) as exc:
         raise OpenSSLObjectError(exc)