1 files changed, 62 insertions, 0 deletions
diff --git a/packages/meshbay-hub/tests/test_hover_scoped.py b/packages/meshbay-hub/tests/test_hover_scoped.py
new file mode 100644
index 0000000..f28dacd
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+++ b/packages/meshbay-hub/tests/test_hover_scoped.py
@@ -0,0 +1,62 @@
+"""
+Every `:hover` rule in style.css is inside `@media (hover: hover)`.
+
+A tap on a touchscreen puts the element in `:hover` and nothing takes it out
+until another element is tapped, so a button tapped once kept its hover colour
+as if still pressed. It was fixed for the music player's buttons alone, then
+reported again on the pager arrows, the nav hamburger and the rest: a rule per
+button only moves the bug to the next button. This holds the whole file.
+"""
+
+from pathlib import Path
+
+import pytest
+
+STYLE = (Path(__file__).resolve().parents[1] / "src" / "meshbay_hub"
+         / "static" / "style.css")
+
+pytestmark = pytest.mark.skipif(not STYLE.exists(),
+                                reason="the stylesheet is not in this checkout")
+
+
+def _hover_rules(source: str) -> list[tuple[int, list[str], str]]:
+    """(line, enclosing at-rule preludes, selector) for each rule naming :hover."""
+    found = []
+    stack: list[str] = []
+    start = 0
+    i = 0
+    while i < len(source):
+        if source.startswith("/*", i):
+            i = source.index("*/", i) + 2
+            start = i
+            continue
+        c = source[i]
+        if c == "{":
+            prelude = source[start:i].strip()
+            if ":hover" in prelude and not prelude.startswith("@"):
+                found.append((source.count("\n", 0, i) + 1, list(stack), prelude))
+            stack.append(prelude)
+            start = i + 1
+        elif c == "}":
+            stack.pop()
+            start = i + 1
+        elif c == ";":
+            start = i + 1
+        i += 1
+    return found
+
+
+def test_every_hover_rule_is_scoped_to_devices_that_hover():
+    rules = _hover_rules(STYLE.read_text(encoding="utf-8"))
+    assert rules, "no :hover rule found, did the parser break?"
+    loose = [f"line {line}: {sel}" for line, stack, sel in rules
+             if not any("(hover: hover)" in at for at in stack)]
+    assert not loose, ("wrap these in @media (hover: hover), a tap leaves them "
+                       "stuck on a touchscreen:\n" + "\n".join(loose))
+
+
+def test_the_parser_catches_a_loose_rule():
+    rules = _hover_rules("/* a { } */ .a:hover { color: red; }\n"
+                         "@media (hover: hover) { .b:hover { color: red; } }")
+    assert [(sel, bool(stack)) for _, stack, sel in rules] == [
+        (".a:hover", False), (".b:hover", True)]