test(v1.4.0-p2): add failing tests for milestones and columns

RED phase: 5 tests in test_collector.py (collect_milestones),
10 tests in test_display.py (render_milestones, parse_columns),
2 tests in test_exporter.py (milestones JSON), 7 tests in
test_cli.py (--milestones, --columns).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_display.py

@@ -401,3 +401,130 @@ class TestSortRepos:
         ]
         result = sort_repos(repos, "activity")
         assert [r.name for r in result] == ["recent", "old-commit", "inactive"]
+
+
+class TestRenderMilestones:
+    """Test the dedicated milestones table rendering."""
+
+    def test_render_milestones_basic(self):
+        """Milestones table displays expected columns."""
+        from gitea_dashboard.collector import MilestoneData
+        from gitea_dashboard.display import render_milestones
+
+        console, buf = _make_console()
+        milestones = [
+            MilestoneData(
+                repo_name="my-repo",
+                title="v1.0",
+                open_issues=2,
+                closed_issues=8,
+                progress_pct=80,
+                due_on="2026-04-01T00:00:00Z",
+                state="open",
+            ),
+        ]
+
+        render_milestones(milestones, console=console)
+        output = buf.getvalue()
+
+        assert "my-repo" in output
+        assert "v1.0" in output
+        assert "80" in output
+
+    def test_render_milestones_empty(self):
+        """Empty list shows informative message."""
+        from gitea_dashboard.display import render_milestones
+
+        console, buf = _make_console()
+
+        render_milestones([], console=console)
+        output = buf.getvalue()
+
+        assert "Aucune milestone" in output
+
+    def test_render_milestones_progress_colors(self):
+        """Progress coloring: green > 80%, yellow 50-80%, red < 50%."""
+        from gitea_dashboard.collector import MilestoneData
+        from gitea_dashboard.display import render_milestones
+
+        console, buf = _make_console()
+        milestones = [
+            MilestoneData("repo", "high", 1, 9, 90, None, "open"),
+            MilestoneData("repo", "mid", 3, 3, 50, None, "open"),
+            MilestoneData("repo", "low", 8, 2, 20, None, "open"),
+        ]
+
+        render_milestones(milestones, console=console)
+        output = buf.getvalue()
+
+        # All three should appear without crash
+        assert "high" in output
+        assert "mid" in output
+        assert "low" in output
+
+
+class TestParseColumns:
+    """Test parse_columns function."""
+
+    def test_parse_columns_all_default(self):
+        """None returns all columns."""
+        from gitea_dashboard.display import AVAILABLE_COLUMNS, parse_columns
+
+        result = parse_columns(None)
+
+        assert result == list(AVAILABLE_COLUMNS.keys())
+
+    def test_parse_columns_inclusion(self):
+        """'name,issues' returns only those columns."""
+        from gitea_dashboard.display import parse_columns
+
+        result = parse_columns("name,issues")
+
+        assert result == ["name", "issues"]
+
+    def test_parse_columns_exclusion(self):
+        """'-description,-commit' returns all except those."""
+        from gitea_dashboard.display import AVAILABLE_COLUMNS, parse_columns
+
+        result = parse_columns("-description,-commit")
+
+        assert "description" not in result
+        assert "commit" not in result
+        assert len(result) == len(AVAILABLE_COLUMNS) - 2
+
+    def test_parse_columns_unknown_raises(self):
+        """Unknown column raises ValueError."""
+        from gitea_dashboard.display import parse_columns
+
+        with pytest.raises(ValueError, match="unknown"):
+            parse_columns("unknown")
+
+    def test_parse_columns_help(self):
+        """'help' returns sentinel list."""
+        from gitea_dashboard.display import parse_columns
+
+        result = parse_columns("help")
+
+        assert result == ["__help__"]
+
+    def test_parse_columns_no_desc_compat(self):
+        """no_desc=True excludes description column."""
+        from gitea_dashboard.display import parse_columns
+
+        result = parse_columns(None, no_desc=True)
+
+        assert "description" not in result
+
+    def test_render_dashboard_with_columns(self):
+        """Only specified columns appear in the output."""
+        from gitea_dashboard.display import render_dashboard
+
+        console, buf = _make_console()
+        repos = [_make_repo(name="test", open_issues=5)]
+
+        render_dashboard(repos, console=console, columns=["name", "issues"])
+        output = buf.getvalue()
+
+        assert "test" in output
+        assert "Description" not in output
+        assert "Release" not in output