chore(test): update tests

Adds additional tests for the interface. Creates a new base test class
GodotXtermTest that adds some additional assert methods. Tests
inheriting from this should override the got_described_class() method.
Add instance of the described class named 'subject' will be created and
added to the scene tree before each test.

test/test_pty.gd

@@ -1,21 +1,86 @@
 # SPDX-FileCopyrightText: 2024 Leroy Hopson <godot-xterm@leroy.nix.nz>
 # SPDX-License-Identifier: MIT
 
-class_name PTYTest extends "res://addons/gut/test.gd"
-
-var pty: PTY
+class_name PTYTest extends GodotXtermTest
 
 
-func before_each():
-	pty = PTY.new()
-	add_child_autofree(pty)
+func get_described_class():
+	return PTY
 
 
-class TestDefaults:
+class TestInterface:
 	extends PTYTest
 
-	func test_default_env() -> void:
-		assert_eq(pty.env, {"TERM": "xterm-256color", "COLORTERM": "truecolor"})
+	## API V2.
 
-	func test_default_use_os_env() -> void:
-		assert_eq(pty.use_os_env, true)
+	# Properties.
+
+	# TODO: Implement cols property.
+	func xtest_has_property_cols() -> void:
+		assert_has_property_with_default_value("cols", 80)
+
+	func test_has_property_env() -> void:
+		assert_has_property_with_default_value(
+			"env", {"TERM": "xterm-256color", "COLORTERM": "truecolor"}
+		)
+
+	# TODO: Implement rows property.
+	func xtest_has_property_rows() -> void:
+		assert_has_property_with_default_value("rows", 24)
+
+	# TODO: Implement terminal_path property.
+	func xtest_has_property_terminal_path() -> void:
+		assert_has_property("terminal_path")
+
+	func test_has_proprty_use_os_env() -> void:
+		assert_has_property_with_default_value("use_os_env", true)
+
+	# Methods.
+
+	func test_has_method_fork():
+		assert_has_method_with_return_type("fork", TYPE_INT)
+
+	func test_has_method_kill():
+		assert_has_method_with_return_type("kill", TYPE_NIL)
+
+	func test_has_method_open():
+		assert_has_method_with_return_type("open", TYPE_INT)
+
+	func test_has_method_resize():
+		assert_has_method_with_return_type("resize", TYPE_NIL)
+
+	func test_has_method_resizev():
+		assert_has_method_with_return_type("resizev", TYPE_NIL)
+
+	func test_has_method_write():
+		assert_has_method_with_return_type("write", TYPE_NIL)
+
+	# Signals.
+
+	func test_has_signal_data_received() -> void:
+		assert_has_signal(subject, "data_received")
+
+	func test_has_signal_exited() -> void:
+		assert_has_signal(subject, "exited")
+
+	# Enums.
+
+	# Added SIGNAL_ prefix to name.
+	func test_has_enum_signal():
+		assert_eq(described_class.SIGNAL_SIGHUP, 1)
+		assert_eq(described_class.SIGNAL_SIGINT, 2)
+		assert_eq(described_class.SIGNAL_SIGQUIT, 3)
+		assert_eq(described_class.SIGNAL_SIGILL, 4)
+		assert_eq(described_class.SIGNAL_SIGTRAP, 5)
+		assert_eq(described_class.SIGNAL_SIGABRT, 6)
+		assert_eq(described_class.SIGNAL_SIGFPE, 8)
+		assert_eq(described_class.SIGNAL_SIGKILL, 9)
+		assert_eq(described_class.SIGNAL_SIGSEGV, 11)
+		assert_eq(described_class.SIGNAL_SIGPIPE, 13)
+		assert_eq(described_class.SIGNAL_SIGALRM, 14)
+		assert_eq(described_class.SIGNAL_SIGTERM, 15)
+
+	## Other tests.
+
+	func test_has_no_visible_children():
+		assert_eq(subject.get_child_count(), 0)