diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 655376c5..0f79ef5f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -14,9 +14,10 @@
     - [4.3.3 The use of GNU extensions](#the-use-of-gnu-extensions)
     - [4.3.4 Naming Conventions](#naming-conventions)
 - [5. Commit Messages](#commit-messages)
-- [6. Submitting Patches](#submitting-patches)
-- [7. Native Language Support](#native-language-support)
-- [8. Upversion](#upversion)
+- [6. Unit Tests](#unit-tests)
+- [7. Submitting Patches](#submitting-patches)
+- [8. Native Language Support](#native-language-support)
+- [9. Upversion](#upversion)
 
 # How to Contribute
 
@@ -345,6 +346,29 @@ This first line should:
 And please wrap the commit message at max 74 characters, otherwise `git log`
 and similar look so weird. URLs and other references are exempt.
 
+# Unit Tests
+
+## Introduction
+
+The tests live in the `t/` directory.
+
+In the bigger scheme of validating that the compositor meets users' needs, unit
+tests do not contribute a great deal. However, they have a role to play in
+providing some verification that stand-alone functions behave as expected.
+
+On this project, writing unit-tests is not compulsory nor do we measure
+coverage. The inclusion of the t/ directory does not signifiy a move towards
+test-driven development. We intend to use unit tests sparingly and only when
+devs find them useful.
+
+## Usage
+
+From repo top level directory:
+
+    meson setup -Dtest=enabled build
+    meson compile -C build/
+    meson test --verbose -C build/
+
 # Submitting patches
 
 Base both bugfixes and new features on `master`.
diff --git a/meson.build b/meson.build
index 4761fbc9..8f9b5a97 100644
--- a/meson.build
+++ b/meson.build
@@ -130,6 +130,11 @@ subdir('include')
 subdir('src')
 subdir('docs')
 
+dep_cmocka = dependency('cmocka', required: get_option('test'))
+if dep_cmocka.found()
+  subdir('t')
+endif
+
 executable(
   meson.project_name(),
   labwc_sources,
diff --git a/meson_options.txt b/meson_options.txt
index d9cb73a8..4d6e8cd5 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -3,3 +3,4 @@ option('xwayland', type: 'feature', value: 'auto', description: 'Enable support
 option('svg', type: 'feature', value: 'enabled', description: 'Enable svg window buttons')
 option('nls', type: 'feature', value: 'auto', description: 'Enable native language support')
 option('static_analyzer', type: 'feature', value: 'disabled', description: 'Run gcc static analyzer')
+option('test', type: 'feature', value: 'disabled', description: 'Run tests')
diff --git a/t/.gitignore b/t/.gitignore
new file mode 100644
index 00000000..a8d6b6c1
--- /dev/null
+++ b/t/.gitignore
@@ -0,0 +1 @@
+*.t
diff --git a/t/buf-simple.c b/t/buf-simple.c
new file mode 100644
index 00000000..47722116
--- /dev/null
+++ b/t/buf-simple.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#define _POSIX_C_SOURCE 200809L
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <cmocka.h>
+#include "common/buf.h"
+#include "common/mem.h"
+
+static void
+test_expand_title(void **state)
+{
+	(void)state;
+
+	struct buf s = BUF_INIT;
+
+	char TEMPLATE[] = "foo ~/bar";
+	char expect[4096];
+	snprintf(expect, sizeof(expect), "foo %s/bar", getenv("HOME"));
+
+	buf_add(&s, TEMPLATE);
+	assert_string_equal(s.data, TEMPLATE);
+	assert_int_equal(s.len, strlen(TEMPLATE));
+
+	// Resolve ~
+	buf_expand_tilde(&s);
+	assert_string_equal(s.data, expect);
+	assert_int_equal(s.len, strlen(expect));
+
+	setenv("bar", "BAR", 1);
+
+	// Resolve $bar and ${bar}
+	s.len = 0;
+	buf_add(&s, "foo $bar baz");
+	buf_expand_shell_variables(&s);
+	assert_string_equal(s.data, "foo BAR baz");
+	assert_int_equal(s.len, 11);
+
+	s.len = 0;
+	buf_add(&s, "foo ${bar} baz");
+	buf_expand_shell_variables(&s);
+	assert_string_equal(s.data, "foo BAR baz");
+	assert_int_equal(s.len, 11);
+
+	// Don't resolve $()
+	s.len = 0;
+	buf_add(&s, "foo $(bar) baz");
+	buf_expand_shell_variables(&s);
+	assert_string_equal(s.data, "foo $(bar) baz");
+	assert_int_equal(s.len, 14);
+
+	unsetenv("bar");
+	free(s.data);
+}
+
+int main(int argc, char **argv)
+{
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(test_expand_title),
+	};
+
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}
diff --git a/t/meson.build b/t/meson.build
new file mode 100644
index 00000000..5517b973
--- /dev/null
+++ b/t/meson.build
@@ -0,0 +1,27 @@
+test_lib = static_library(
+  'test_lib',
+  sources: files(
+    '../src/common/buf.c',
+    '../src/common/mem.c',
+    '../src/common/string-helpers.c'
+  ),
+  include_directories: [labwc_inc],
+  dependencies: [dep_cmocka],
+)
+
+tests = [
+  'buf-simple',
+]
+
+foreach t : tests
+  test(
+    'test_@0@'.format(t),
+    executable(
+      'test_@0@'.format(t),
+      sources: '@0@.c'.format(t),
+      include_directories: [labwc_inc],
+      link_with: [test_lib],
+    ),
+    is_parallel: false,
+  )
+endforeach