[homeassistant] Share the Python list parser between the platforms (#20793)

tests/components/homeassistant/test_python_list.cpp

@@ -0,0 +1,62 @@
+#include <gtest/gtest.h>
+
+#include <string>
+#include <vector>
+
+#include "esphome/components/homeassistant/homeassistant.h"
+
+namespace esphome::homeassistant::testing {
+
+namespace {
+
+struct Parsed {
+  bool valid;
+  std::vector<std::string> items;
+};
+
+Parsed parse(const char *text) {
+  Parsed result;
+  std::string item;
+  result.valid = parse_python_list(
+      StringRef(text), [&](char c) { item += c; },
+      [&]() {
+        result.items.push_back(item);
+        item.clear();
+      });
+  return result;
+}
+
+}  // namespace
+
+TEST(PythonList, ReadsStringsWithTheirEscapes) {
+  auto parsed = parse(R"(['Low', "It's high", 'caf\xe9'])");
+  ASSERT_TRUE(parsed.valid);
+  ASSERT_EQ(parsed.items.size(), 3u);
+  EXPECT_EQ(parsed.items[0], "Low");
+  EXPECT_EQ(parsed.items[1], "It's high");
+  EXPECT_EQ(parsed.items[2], "caf\xc3\xa9");
+}
+
+TEST(PythonList, ReadsTheValueOfEnumMembers) {
+  auto parsed = parse("[<ColorMode.HS: 'hs'>, <ColorMode.COLOR_TEMP: 'color_temp'>]");
+  ASSERT_TRUE(parsed.valid);
+  ASSERT_EQ(parsed.items.size(), 2u);
+  EXPECT_EQ(parsed.items[0], "hs");
+  EXPECT_EQ(parsed.items[1], "color_temp");
+}
+
+TEST(PythonList, AcceptsAnEmptyList) {
+  auto parsed = parse("[]");
+  EXPECT_TRUE(parsed.valid);
+  EXPECT_TRUE(parsed.items.empty());
+}
+
+TEST(PythonList, RejectsMalformedLists) {
+  for (const char *text : {"", "[", "['a'", "['a',", "['a' 'b']", "['a'] x", "[1]", "['a\\q']", "[<ColorMode.HS: 'hs'",
+                           "[<ColorMode.HS>]", "[<ColorMode.HS>, <ColorMode.RGB: 'rgb'>]",
+                           "[<ColorMode.HS: 'hs', <ColorMode.RGB: 'rgb'>]", "[<X: 'a' 'b'>]", "[<X 'a'>]", "[<'a'>]"}) {
+    EXPECT_FALSE(parse(text).valid) << text;
+  }
+}
+
+}  // namespace esphome::homeassistant::testing