diff --git a/lib/kunit/assert.c b/lib/kunit/assert.c
new file mode 100644
index 0000000..33acdaa
--- /dev/null
+++ b/lib/kunit/assert.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Assertion and expectation serialization API.
+ *
+ * Copyright (C) 2019, Google LLC.
+ * Author: Brendan Higgins <brendanhiggins@google.com>
+ */
+#include <kunit/assert.h>
+#include <kunit/test.h>
+
+#include "string-stream.h"
+
+void kunit_base_assert_format(const struct kunit_assert *assert,
+			      struct string_stream *stream)
+{
+	const char *expect_or_assert = NULL;
+
+	switch (assert->type) {
+	case KUNIT_EXPECTATION:
+		expect_or_assert = "EXPECTATION";
+		break;
+	case KUNIT_ASSERTION:
+		expect_or_assert = "ASSERTION";
+		break;
+	}
+
+	string_stream_add(stream, "%s FAILED at %s:%d\n",
+			 expect_or_assert, assert->file, assert->line);
+}
+EXPORT_SYMBOL_GPL(kunit_base_assert_format);
+
+void kunit_assert_print_msg(const struct kunit_assert *assert,
+			    struct string_stream *stream)
+{
+	if (assert->message.fmt)
+		string_stream_add(stream, "\n%pV", &assert->message);
+}
+EXPORT_SYMBOL_GPL(kunit_assert_print_msg);
+
+void kunit_fail_assert_format(const struct kunit_assert *assert,
+			      struct string_stream *stream)
+{
+	kunit_base_assert_format(assert, stream);
+	string_stream_add(stream, "%pV", &assert->message);
+}
+EXPORT_SYMBOL_GPL(kunit_fail_assert_format);
+
+void kunit_unary_assert_format(const struct kunit_assert *assert,
+			       struct string_stream *stream)
+{
+	struct kunit_unary_assert *unary_assert = container_of(
+			assert, struct kunit_unary_assert, assert);
+
+	kunit_base_assert_format(assert, stream);
+	if (unary_assert->expected_true)
+		string_stream_add(stream,
+				  KUNIT_SUBTEST_INDENT "Expected %s to be true, but is false\n",
+				  unary_assert->condition);
+	else
+		string_stream_add(stream,
+				  KUNIT_SUBTEST_INDENT "Expected %s to be false, but is true\n",
+				  unary_assert->condition);
+	kunit_assert_print_msg(assert, stream);
+}
+EXPORT_SYMBOL_GPL(kunit_unary_assert_format);
+
+void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert,
+				     struct string_stream *stream)
+{
+	struct kunit_ptr_not_err_assert *ptr_assert = container_of(
+			assert, struct kunit_ptr_not_err_assert, assert);
+
+	kunit_base_assert_format(assert, stream);
+	if (!ptr_assert->value) {
+		string_stream_add(stream,
+				  KUNIT_SUBTEST_INDENT "Expected %s is not null, but is\n",
+				  ptr_assert->text);
+	} else if (IS_ERR(ptr_assert->value)) {
+		string_stream_add(stream,
+				  KUNIT_SUBTEST_INDENT "Expected %s is not error, but is: %ld\n",
+				  ptr_assert->text,
+				  PTR_ERR(ptr_assert->value));
+	}
+	kunit_assert_print_msg(assert, stream);
+}
+EXPORT_SYMBOL_GPL(kunit_ptr_not_err_assert_format);
+
+void kunit_binary_assert_format(const struct kunit_assert *assert,
+				struct string_stream *stream)
+{
+	struct kunit_binary_assert *binary_assert = container_of(
+			assert, struct kunit_binary_assert, assert);
+
+	kunit_base_assert_format(assert, stream);
+	string_stream_add(stream,
+			  KUNIT_SUBTEST_INDENT "Expected %s %s %s, but\n",
+			  binary_assert->left_text,
+			  binary_assert->operation,
+			  binary_assert->right_text);
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %lld\n",
+			  binary_assert->left_text,
+			  binary_assert->left_value);
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %lld",
+			  binary_assert->right_text,
+			  binary_assert->right_value);
+	kunit_assert_print_msg(assert, stream);
+}
+EXPORT_SYMBOL_GPL(kunit_binary_assert_format);
+
+void kunit_binary_ptr_assert_format(const struct kunit_assert *assert,
+				    struct string_stream *stream)
+{
+	struct kunit_binary_ptr_assert *binary_assert = container_of(
+			assert, struct kunit_binary_ptr_assert, assert);
+
+	kunit_base_assert_format(assert, stream);
+	string_stream_add(stream,
+			  KUNIT_SUBTEST_INDENT "Expected %s %s %s, but\n",
+			  binary_assert->left_text,
+			  binary_assert->operation,
+			  binary_assert->right_text);
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %px\n",
+			  binary_assert->left_text,
+			  binary_assert->left_value);
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %px",
+			  binary_assert->right_text,
+			  binary_assert->right_value);
+	kunit_assert_print_msg(assert, stream);
+}
+EXPORT_SYMBOL_GPL(kunit_binary_ptr_assert_format);
+
+void kunit_binary_str_assert_format(const struct kunit_assert *assert,
+				    struct string_stream *stream)
+{
+	struct kunit_binary_str_assert *binary_assert = container_of(
+			assert, struct kunit_binary_str_assert, assert);
+
+	kunit_base_assert_format(assert, stream);
+	string_stream_add(stream,
+			  KUNIT_SUBTEST_INDENT "Expected %s %s %s, but\n",
+			  binary_assert->left_text,
+			  binary_assert->operation,
+			  binary_assert->right_text);
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %s\n",
+			  binary_assert->left_text,
+			  binary_assert->left_value);
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %s",
+			  binary_assert->right_text,
+			  binary_assert->right_value);
+	kunit_assert_print_msg(assert, stream);
+}
+EXPORT_SYMBOL_GPL(kunit_binary_str_assert_format);