diff --git a/doc/README.commands b/doc/README.commands
index 716ad22..229f86d 100644
--- a/doc/README.commands
+++ b/doc/README.commands
@@ -134,3 +134,53 @@
 	.u_boot_list : {
 		KEEP(*(SORT(.u_boot_list*)));
 	}
+
+Writing tests
+-------------
+
+All new commands should have tests. Tests for existing commands are very
+welcome.
+
+It is fairly easy to write a test for a command. Enable it in sandbox, and
+then add code that runs the command and checks the output.
+
+Here is an example:
+
+/* Test 'acpi items' command */
+static int dm_test_acpi_cmd_items(struct unit_test_state *uts)
+{
+	struct acpi_ctx ctx;
+	void *buf;
+
+	buf = malloc(BUF_SIZE);
+	ut_assertnonnull(buf);
+
+	ctx.current = buf;
+	ut_assertok(acpi_fill_ssdt(&ctx));
+	console_record_reset();
+	run_command("acpi items", 0);
+	ut_assert_nextline("dev 'acpi-test', type 1, size 2");
+	ut_assert_nextline("dev 'acpi-test2', type 1, size 2");
+	ut_assert_console_end();
+
+	ctx.current = buf;
+	ut_assertok(acpi_inject_dsdt(&ctx));
+	console_record_reset();
+	run_command("acpi items", 0);
+	ut_assert_nextline("dev 'acpi-test', type 2, size 2");
+	ut_assert_nextline("dev 'acpi-test2', type 2, size 2");
+	ut_assert_console_end();
+
+	console_record_reset();
+	run_command("acpi items -d", 0);
+	ut_assert_nextline("dev 'acpi-test', type 2, size 2");
+	ut_assert_nextlines_are_dump(2);
+	ut_assert_nextline("%s", "");
+	ut_assert_nextline("dev 'acpi-test2', type 2, size 2");
+	ut_assert_nextlines_are_dump(2);
+	ut_assert_nextline("%s", "");
+	ut_assert_console_end();
+
+	return 0;
+}
+DM_TEST(dm_test_acpi_cmd_items, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);