diff --git a/test_convert_command.py b/test_convert_command.py
new file mode 100644
index 0000000..f28c6aa
--- /dev/null
+++ b/test_convert_command.py
@@ -0,0 +1,120 @@
+import shutil
+import unittest
+
+from shell_command import (
+    ShellCommand, ConvertCommand
+)
+
+
+class TestConvertCommand(unittest.TestCase):
+    """Test the ConvertCommand class.
+    """
+
+    # Local ConvertCommand.
+    command = None
+
+    # Path to convert executable.
+    expected_executable = shutil.which("convert")
+
+    # Expected base options.
+    expected_base_options = [
+        "-size", "2048x1536",
+        "-density", "600",
+        "xc:dimgrey", "null:",
+        "("
+    ]
+
+    # Expected input options.
+    expected_input_options = [
+        "foo",
+        "-resize", "2048x1536",
+        "-background", "white", 
+        "-alpha", "remove",
+        "-type", "truecolor",
+        "-define", "colorspace:auto-grayscale=off",
+    ]
+
+    # Expected output options.
+    expected_output_options = [
+        ")",
+        "-gravity", "center",
+        "-layers", "composite",
+        "-flatten",
+        "bar",
+    ]
+
+    def setUp(self):
+        """Initialisation. Make sure the input and output options are
+        explicitly set otherwise they hang around from previous tests.
+        """
+        self.command = ConvertCommand(
+            input_options=["foo"], output_options=["bar"])
+
+    def tearDown(self):
+        """Cleanup.
+        """
+        self.command = None
+    
+    def test_base_options(self):
+        """Test that base options match expected.
+        """
+        self.assertEqual(
+            self.command._base_options, self.expected_base_options)
+    
+    def test_input_options(self):
+        """Test that input options match expected.
+        """
+        self.assertEqual(
+            self.command.input_options, self.expected_input_options)
+    
+    def test_output_options(self):
+        """Test that output options match expected.
+        """
+        self.assertEqual(
+            self.command.output_options, self.expected_output_options)
+    
+    def test_executable_string(self):
+        """Test that executable path matches expected.
+        """
+        self.assertEqual(self.command.executable_string(quote=False),
+            self.expected_executable)
+        # Note: don't explicitly specify quoted value, because
+        # the executable path will vary across different systems.
+        self.assertEqual(self.command.executable_string(quote=True),
+            ShellCommand.shellquote(self.expected_executable))
+
+    def test_argument_string(self):
+        """Test that the argument string matches expected.
+        """
+        args = (self.expected_base_options + self.expected_input_options +
+            self.expected_output_options)
+        self.assertEqual(self.command.argument_string(quote=False),
+            " ".join(args))
+        self.assertEqual(self.command.argument_string(quote=True),
+            " ".join([ShellCommand.shellquote(a) for a in args]))
+
+    def test_argument_list(self):
+        """Test that the argument list matches expected.
+        """
+        self.assertEqual(self.command.argument_list(),
+            self.expected_base_options + self.expected_input_options +
+            self.expected_output_options)
+
+    def test_command_string(self):
+        """Test that the command string matches expected.
+        """
+        args = (self.expected_base_options + self.expected_input_options +
+            self.expected_output_options)
+        expected_cmd_unquoted = (
+            "{exe} {arg}".format(exe=self.expected_executable,
+                arg=" ".join(args))
+        )
+        expected_cmd_quoted = (
+            '{exe} {arg}'.format(
+                exe=ShellCommand.shellquote(self.expected_executable),
+                arg=" ".join([ShellCommand.shellquote(a) for a in args]))
+        )
+        self.assertEqual(self.command.command_string(quote=False),
+            expected_cmd_unquoted)
+        self.assertEqual(self.command.command_string(quote=True),
+            expected_cmd_quoted)