chore: import upstream snapshot with attribution

tests/test_replace_or_append_section.py

@@ -0,0 +1,62 @@
+"""#1688 - graphify's shared-file section update must not destroy user content.
+
+_replace_or_append_section used to locate its marker (`## graphify`) as a
+substring, so a bullet or inline reference to the section became the replace
+anchor and every line from there to the next heading was deleted. The marker is
+now matched only as an exact heading line.
+"""
+from __future__ import annotations
+
+from graphify.__main__ import _replace_or_append_section
+
+MARKER = "## graphify"
+NEW = "## graphify\n\nThis project has a knowledge graph at graphify-out/.\n"
+
+
+def test_inline_reference_to_marker_is_not_treated_as_the_section():
+    before = (
+        "# My Project\n\n"
+        "## Setup\n"
+        "- See the `## graphify` section for graph usage.\n\n"
+        "## Release Process\n"
+        "Critical steps that must not be lost.\n"
+    )
+    after = _replace_or_append_section(before, MARKER, NEW)
+    assert "See the `## graphify` section" in after       # bullet preserved
+    assert "Critical steps that must not be lost" in after  # later section preserved
+    assert "knowledge graph at graphify-out/" in after      # section still added
+
+
+def test_real_section_is_replaced_in_place():
+    before = (
+        "# P\n\n## Setup\n- do things\n\n"
+        "## graphify\n\nOLD text.\n\n"
+        "## Release\nkeep me\n"
+    )
+    after = _replace_or_append_section(before, MARKER, NEW)
+    assert "OLD text." not in after
+    assert "knowledge graph at graphify-out/" in after
+    assert "do things" in after and "keep me" in after
+
+
+def test_reinstall_is_idempotent():
+    once = _replace_or_append_section("# P\n\n## Setup\n- x\n", MARKER, NEW)
+    twice = _replace_or_append_section(once, MARKER, NEW)
+    assert once.split("\n").count(MARKER) == 1
+    assert twice.split("\n").count(MARKER) == 1
+
+
+def test_append_when_no_real_heading():
+    before = "# P\n\n## Setup\n- x\n"
+    after = _replace_or_append_section(before, MARKER, NEW)
+    assert "- x" in after
+    assert after.split("\n").count(MARKER) == 1
+
+
+def test_prefers_last_heading_when_duplicated():
+    before = "## graphify\nstale early copy\n\n## Other\nmid\n\n## graphify\nreal trailing copy\n"
+    after = _replace_or_append_section(before, MARKER, NEW)
+    # the trailing real section is replaced; the earlier stray heading + the
+    # user's "mid" content are left intact
+    assert "mid" in after
+    assert "knowledge graph at graphify-out/" in after