diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 00000000..173eeaec
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,30 @@
+name: tests
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  pytest:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install pytest
+        run: python -m pip install --upgrade pip pytest
+
+      - name: Run unit tests
+        # The suite imports only dependency-free host-side modules and resolves
+        # them via pythonpath = ["src"] (see pyproject.toml), so the full
+        # package install is not required to run it.
+        run: pytest
diff --git a/pyproject.toml b/pyproject.toml
index fe951add..90b2587a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -45,4 +45,13 @@ reversec = "src/reversec"
 pysolar = "src/pysolar"
 
 [tool.setuptools.dynamic]
-version = { attr = "drozer.__version__" }
\ No newline at end of file
+version = { attr = "drozer.__version__" }
+
+[project.optional-dependencies]
+test = ["pytest"]
+
+[tool.pytest.ini_options]
+# The package sources live under src/; expose them so the unit tests can be
+# run directly (without an editable install) via `pytest`.
+pythonpath = ["src"]
+testpaths = ["tests"]
\ No newline at end of file
diff --git a/tests/test_android.py b/tests/test_android.py
new file mode 100644
index 00000000..90c785e1
--- /dev/null
+++ b/tests/test_android.py
@@ -0,0 +1,72 @@
+"""Unit tests for drozer.android.Intent (host-side logic only).
+
+These cover the pure-Python behaviour of Intent that does not require a live
+Android session: validity checks, default attributes and flag combination.
+"""
+
+import argparse
+
+from drozer.android import Intent
+
+
+class TestIntentValidity:
+
+    def test_empty_intent_is_invalid(self):
+        # An Intent must carry at least an action or a component.
+        assert Intent().isValid() is False
+
+    def test_action_makes_intent_valid(self):
+        assert Intent(action="android.intent.action.VIEW").isValid() is True
+
+    def test_component_makes_intent_valid(self):
+        assert Intent(component=["com.example", "com.example.Activity"]).isValid() is True
+
+
+class TestIntentDefaults:
+
+    def test_attributes_default_to_none(self):
+        intent = Intent()
+        assert intent.action is None
+        assert intent.category is None
+        assert intent.component is None
+        assert intent.data_uri is None
+        assert intent.extras is None
+        assert intent.flags is None
+        assert intent.mimetype is None
+
+
+class TestIntentFlags:
+
+    # __build_flags is name-mangled; access it directly to unit-test the pure
+    # flag-combination logic without needing a Java context.
+    def _build(self, flags):
+        return Intent()._Intent__build_flags(flags)
+
+    def test_single_named_flag(self):
+        assert self._build(["ACTIVITY_NEW_TASK"]) == 0x10000000
+
+    def test_named_flags_are_ored_together(self):
+        assert self._build(["ACTIVITY_NEW_TASK", "ACTIVITY_CLEAR_TOP"]) == 0x14000000
+
+    def test_hexadecimal_flag(self):
+        assert self._build(["0x10000000"]) == 0x10000000
+
+    def test_empty_flag_list_is_zero(self):
+        assert self._build([]) == 0x00000000
+
+
+class TestIntentFromParser:
+
+    def test_builds_intent_from_namespace(self):
+        namespace = argparse.Namespace(
+            action="android.intent.action.MAIN",
+            category=None,
+            component=None,
+            data_uri=None,
+            extras=[],
+            flags=[],
+            mimetype=None,
+        )
+        intent = Intent.fromParser(namespace)
+        assert intent.action == "android.intent.action.MAIN"
+        assert intent.isValid() is True
diff --git a/tests/test_fs.py b/tests/test_fs.py
new file mode 100644
index 00000000..629fea13
--- /dev/null
+++ b/tests/test_fs.py
@@ -0,0 +1,28 @@
+"""Unit tests for reversec.common.fs."""
+
+from reversec.common import fs
+
+
+class TestReadWrite:
+
+    def test_write_then_read_round_trips(self, tmp_path):
+        target = str(tmp_path / "data.bin")
+        written = fs.write(target, b"hello world")
+        assert written == len(b"hello world")
+        assert fs.read(target) == b"hello world"
+
+    def test_read_missing_file_returns_none(self, tmp_path):
+        assert fs.read(str(tmp_path / "does-not-exist")) is None
+
+    def test_read_as_text(self, tmp_path):
+        target = str(tmp_path / "data.txt")
+        fs.write(target, b"plain text")
+        assert fs.read(target, "r") == "plain text"
+
+
+class TestTouch:
+
+    def test_touch_creates_empty_file(self, tmp_path):
+        target = str(tmp_path / "touched")
+        fs.touch(target)
+        assert fs.read(target) == b""
diff --git a/tests/test_list.py b/tests/test_list.py
new file mode 100644
index 00000000..149d388d
--- /dev/null
+++ b/tests/test_list.py
@@ -0,0 +1,35 @@
+"""Unit tests for reversec.common.list."""
+
+from reversec.common.list import chunk, flatten
+
+
+class TestChunk:
+
+    def test_splits_into_even_chunks(self):
+        assert list(chunk([1, 2, 3, 4], 2)) == [[1, 2], [3, 4]]
+
+    def test_final_chunk_may_be_short(self):
+        assert list(chunk([1, 2, 3, 4, 5], 2)) == [[1, 2], [3, 4], [5]]
+
+    def test_empty_list_yields_nothing(self):
+        assert list(chunk([], 2)) == []
+
+    def test_chunk_larger_than_list(self):
+        assert list(chunk([1, 2], 10)) == [[1, 2]]
+
+
+class TestFlatten:
+
+    def test_flattens_nested_lists(self):
+        assert list(flatten([1, [2, 3], [4, [5, 6]]])) == [1, 2, 3, 4, 5, 6]
+
+    def test_flattens_tuples(self):
+        assert list(flatten([1, (2, 3)])) == [1, 2, 3]
+
+    def test_strings_are_not_flattened(self):
+        # Strings are iterable but must be treated as scalar values, otherwise
+        # they would be exploded into individual characters.
+        assert list(flatten(["ab", ["cd"]])) == ["ab", "cd"]
+
+    def test_empty_list(self):
+        assert list(flatten([])) == []
diff --git a/tests/test_text.py b/tests/test_text.py
new file mode 100644
index 00000000..8a42027c
--- /dev/null
+++ b/tests/test_text.py
@@ -0,0 +1,27 @@
+"""Unit tests for reversec.common.text."""
+
+from reversec.common.text import indent, wrap
+
+
+class TestIndent:
+
+    def test_prefixes_every_line(self):
+        assert indent("a\nb\nc", "  ") == "  a\n  b\n  c"
+
+    def test_single_line(self):
+        assert indent("hello", ">> ") == ">> hello"
+
+    def test_empty_string_still_prefixed(self):
+        assert indent("", ">") == ">"
+
+
+class TestWrap:
+
+    def test_text_shorter_than_width_is_unchanged(self):
+        assert wrap("one two three", 1000) == "one two three"
+
+    def test_wraps_on_word_boundaries(self):
+        assert wrap("aaa bbb ccc", 5) == "aaa\nbbb\nccc"
+
+    def test_existing_newlines_are_preserved(self):
+        assert "\n" in wrap("first line\nsecond line", 1000)
diff --git a/tests/test_util.py b/tests/test_util.py
new file mode 100644
index 00000000..18c6fe9f
--- /dev/null
+++ b/tests/test_util.py
@@ -0,0 +1,47 @@
+"""Unit tests for drozer.util."""
+
+import argparse
+
+import pytest
+
+from drozer.util import DefaultHost, DefaultPort, StoreZeroOrTwo, parse_server
+
+
+class TestParseServer:
+
+    def test_none_uses_defaults(self):
+        host, port = parse_server(None)
+        # DefaultHost ("localhost") is resolved to an address by parse_server.
+        assert port == DefaultPort
+        assert host  # a non-empty resolved address
+
+    def test_host_only_uses_default_port(self):
+        assert parse_server("127.0.0.1") == ("127.0.0.1", DefaultPort)
+
+    def test_host_and_port(self):
+        assert parse_server("10.0.0.5:9999") == ("10.0.0.5", 9999)
+
+    def test_port_is_returned_as_int(self):
+        _, port = parse_server("127.0.0.1:1234")
+        assert isinstance(port, int) and port == 1234
+
+
+class TestStoreZeroOrTwo:
+
+    def _action(self):
+        return StoreZeroOrTwo(option_strings=["--ssl"], dest="ssl")
+
+    def test_accepts_zero_arguments(self):
+        action, namespace = self._action(), argparse.Namespace()
+        action(None, namespace, [], None)
+        assert namespace.ssl == []
+
+    def test_accepts_two_arguments(self):
+        action, namespace = self._action(), argparse.Namespace()
+        action(None, namespace, ["cert.pem", "key.pem"], None)
+        assert namespace.ssl == ["cert.pem", "key.pem"]
+
+    def test_rejects_one_argument(self):
+        action, namespace = self._action(), argparse.Namespace()
+        with pytest.raises(argparse.ArgumentTypeError):
+            action(None, namespace, ["cert.pem"], None)