Add test class for key generation

Genertae test_suite_psa_crypto_generate_key.generated.data.
Use test_suite_psa_crypto_generate_key.function as a test function.

Signed-off-by: Przemyslaw Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/scripts/mbedtls_dev/test_case.py b/scripts/mbedtls_dev/test_case.py
index d01e143..11117fc 100644
--- a/scripts/mbedtls_dev/test_case.py
+++ b/scripts/mbedtls_dev/test_case.py
@@ -42,6 +42,7 @@
         self.dependencies = [] #type: List[str]
         self.function = None #type: Optional[str]
         self.arguments = [] #type: List[str]
+        self.result = '' #type: str
 
     def add_comment(self, *lines: str) -> None:
         self.comments += lines
@@ -58,6 +59,9 @@
     def set_arguments(self, arguments: List[str]) -> None:
         self.arguments = arguments
 
+    def set_result(self, result: str) -> None:
+        self.result = result
+
     def check_completeness(self) -> None:
         if self.description is None:
             raise MissingDescription
@@ -81,9 +85,11 @@
         out.write(self.description + '\n')
         if self.dependencies:
             out.write('depends_on:' + ':'.join(self.dependencies) + '\n')
-        out.write(self.function + ':' + ':'.join(self.arguments) + '\n')
-
-
+        out.write(self.function + ':' + ':'.join(self.arguments))
+        if self.result:
+            out.write(':' + self.result + '\n')
+        else:
+            out.write('\n')
 
 def write_data_file(filename: str,
                     test_cases: Iterable[TestCase],