diff --git a/tests/scripts/test_psa_constant_names.py b/tests/scripts/test_psa_constant_names.py
index e640408..e261b4f 100755
--- a/tests/scripts/test_psa_constant_names.py
+++ b/tests/scripts/test_psa_constant_names.py
@@ -338,48 +338,52 @@
                    include_path=include_path, keep_c=keep_c)
     return expressions, values
 
-def do_test(options, inputs, type_word):
-    """Test psa_constant_names for the specified type.
+class Tests:
+    """An object representing tests and their results."""
 
-    Run program on names.
-    Use inputs to figure out what arguments to pass to macros that
-    take arguments.
+    def __init__(self, options):
+        self.options = options
+        self.count = 0
+        self.errors = []
 
-    Return ``(count, errors)`` where ``count`` is the number of expressions
-    that have been tested and ``errors`` is the list of errors that were
-    encountered.
-    """
-    expressions, values = collect_values(inputs, type_word,
-                                         include_path=options.include,
-                                         keep_c=options.keep_c)
-    output = subprocess.check_output([options.program, type_word] + values)
-    outputs = output.decode('ascii').strip().split('\n')
-    errors = [(type_word, expr, value, output)
-              for (expr, value, output) in zip(expressions, values, outputs)
-              if normalize(expr) != normalize(output)]
-    return len(expressions), errors
+    def run_one(self, inputs, type_word):
+        """Test psa_constant_names for the specified type.
 
-def report_errors(errors):
-    """Describe each case where the output is not as expected."""
-    for type_word, name, value, output in errors:
-        print('For {} "{}", got "{}" (value: {})'
-              .format(type_word, name, output, value))
+        Run the program on the names for this type.
+        Use the inputs to figure out what arguments to pass to macros that
+        take arguments.
+        """
+        expressions, values = collect_values(inputs, type_word,
+                                             include_path=self.options.include,
+                                             keep_c=self.options.keep_c)
+        output = subprocess.check_output([self.options.program, type_word] +
+                                         values)
+        outputs = output.decode('ascii').strip().split('\n')
+        self.count += len(expressions)
+        for expr, value, output in zip(expressions, values, outputs):
+            if normalize(expr) != normalize(output):
+                self.errors.append((type_word, expr, value, output))
 
-def run_tests(options, inputs):
-    """Run psa_constant_names on all the gathered inputs.
+    def run_all(self, inputs):
+        """Run psa_constant_names on all the gathered inputs."""
+        for type_word in ['status', 'algorithm', 'ecc_curve', 'dh_group',
+                          'key_type', 'key_usage']:
+            self.run_one(inputs, type_word)
 
-    Return a tuple (count, errors) where count is the total number of inputs
-    that were tested and errors is the list of cases where the output was
-    not as expected.
-    """
-    count = 0
-    errors = []
-    for type_word in ['status', 'algorithm', 'ecc_curve', 'dh_group',
-                      'key_type', 'key_usage']:
-        c, e = do_test(options, inputs, type_word)
-        count += c
-        errors += e
-    return count, errors
+    def report(self, out):
+        """Describe each case where the output is not as expected.
+
+        Write the errors to ``out``.
+        Also write a total.
+        """
+        for type_word, name, value, output in self.errors:
+            out.write('For {} "{}", got "{}" (value: {})\n'
+                      .format(type_word, name, output, value))
+        out.write('{} test cases'.format(self.count))
+        if self.errors:
+            out.write(', {} FAIL\n'.format(len(self.errors)))
+        else:
+            out.write(' PASS\n')
 
 HEADERS = ['psa/crypto.h', 'psa/crypto_extra.h', 'psa/crypto_values.h']
 TEST_SUITES = ['tests/suites/test_suite_psa_crypto_metadata.data']
@@ -401,12 +405,10 @@
     options = parser.parse_args()
     headers = [os.path.join(options.include[0], h) for h in HEADERS]
     inputs = gather_inputs(headers, TEST_SUITES)
-    count, errors = run_tests(options, inputs)
-    report_errors(errors)
-    if errors == []:
-        print('{} test cases PASS'.format(count))
-    else:
-        print('{} test cases, {} FAIL'.format(count, len(errors)))
+    tests = Tests(options)
+    tests.run_all(inputs)
+    tests.report(sys.stdout)
+    if tests.errors:
         exit(1)
 
 if __name__ == '__main__':