Add `test_lines_justify`

tests/test_containers.py

@@ -1,6 +1,7 @@
 from rich.console import Console
 from rich.containers import Lines, Renderables
-from rich.text import Text
+from rich.text import Span, Text
+from rich.style import Style
 
 
 def test_renderables_measure():
@@ -32,3 +33,24 @@ def test_lines_rich_console():
 
     result = list(lines.__rich_console__(console, console.options))
     assert result == [Text("foo")]
+
+
+def test_lines_justify():
+    console = Console()
+    lines1 = Lines([Text("foo"), Text("test")])
+    lines1.justify(console, 10, justify="left")
+    assert lines1._lines == [Text("foo       "), Text("test      ")]
+    lines1.justify(console, 10, justify="center")
+    assert lines1._lines == [Text("   foo    "), Text("   test   ")]
+    lines1.justify(console, 10, justify="right")
+    assert lines1._lines == [Text("       foo"), Text("      test")]
+
+    lines2 = Lines([Text("foo  bar"), Text("test")])
+    lines2.justify(console, 7, justify="full")
+    assert lines2._lines == [
+        Text(
+            "foo bar",
+            spans=[Span(0, 3, ""), Span(3, 4, Style.parse("none")), Span(4, 7, "")],
+        ),
+        Text("test"),
+    ]