fix: correct GPS command family and enhance command tests

Fixed critical bug where :gT# was incorrectly hardcoded as GetInfo
family instead of GPS family. This protocol-level bug was discovered
through comprehensive documentation comparison with LX200CommandSet.md.

The LX200 protocol uses case-sensitive command families:
- :gT# (lowercase g) = GPS family: 'Set Mount Time from GPS'
  Blocking call up to 2 minutes, returns 1 (success) or 0 (timeout)
- :GT# (uppercase G) = GetInfo family: 'Get tracking rate'
  Instant query returning tracking frequency

Bug Impact:
- Misrouting could cause 2-minute hangs when expecting instant query
- Firmware command dispatch would route to wrong handler
- Integration with ASCOM/INDI/Stellarium could fail unexpectedly

Changes to lib/lx200/src/lx200.cpp:
- Removed incorrect special case forcing :gT# to GetInfo family
- Added clarifying comments about lowercase vs uppercase distinction
- Now correctly routes based on first character ('g' vs 'G')

Changes to tests/lib/lx200/src/test_commands.cpp:
- Split test_getinfo_commands to test only uppercase G commands
- Created test_gps_commands for lowercase g commands
  * :gT# - Set mount time from GPS
  * :gTnnn# - Set mount time with timeout parameter [OAT]
  * :g+# - Turn on GPS power
  * :g-# - Turn off GPS power
- Created test_library_commands for L family
  * :LI# - Get object information
  * :LMNNNN# - Select Messier object with parameter extraction
- Created test_extended_oat_commands for X family (OAT extensions)
  * :XFR# - Factory reset
- Added comprehensive documentation for each test explaining:
  * Command purpose and behavior
  * References to LX200CommandSet.md appendices
  * Critical distinctions (blocking vs instant, case sensitivity)
  * OAT-specific extensions vs standard Meade commands

Test Results:
- All 248/248 tests passing (100%)
- Added 8 new test cases (+3.3% coverage)
- GPS family: 4 commands tested
- Library family: 2 commands tested (+ parameter extraction)
- Extended family: 1 command tested
- GetInfo family: corrected to test :GT# (uppercase) instead of :gT#

This fix addresses documentation comparison findings and ensures
proper command routing in the C++20 rewrite. Case sensitivity in
LX200 protocol is critical for correct telescope control behavior.

Author: andre-stefanov

OpenAstroFirmware.code-workspace

@@ -16,7 +16,8 @@
 		"terminal.integrated.defaultProfile.linux": "zsh",
 		"files.associations": {
 			"string_view": "cpp",
-			"array": "cpp"
+			"array": "cpp",
+			"optional": "cpp"
 		}
 	}
 }

lib/lx200/src/lx200.cpp

@@ -94,11 +94,9 @@ std::optional<Command> ParserState::get_command() noexcept
         name == "SC" || name == "SL" || name == "SG" || name == "SH") {
         family = CommandFamily::DateTime;
     }
-    // Special case: gT (update time from GPS) is GetInfo, not GPS
-    else if (name == "gT") {
-        family = CommandFamily::GetInfo;
-    }
     // Default: use first character mapping
+    // NOTE: :gT# (lowercase g) is GPS family, not GetInfo
+    // (:GT# with uppercase G is GetInfo - "Get tracking rate")
     else {
         family = identify_family(name.empty() ? '\0' : name[0]);
     }

tests/lib/lx200/src/test_commands.cpp

@@ -110,7 +110,7 @@ ZTEST(lx200, test_focus_commands)
 }
 
 /**
- * @brief Test GetInfo command family (G lowercase g)
+ * @brief Test GetInfo command family (uppercase G)
  */
 ZTEST(lx200, test_getinfo_commands)
 {
@@ -124,14 +124,73 @@ ZTEST(lx200, test_getinfo_commands)
 	zassert_true(cmd.has_value(), "Should parse GR command");
 	zassert_equal(cmd->family, CommandFamily::GetInfo, "GR should be GetInfo family");
 
-	// :gT# - Get tracking rate
+	// :GC# - Get calendar date
 	parser.reset();
-	for (const char c : std::string_view(":gT#")) {
+	for (const char c : std::string_view(":GC#")) {
+		parser.feed_character(c);
+	}
+	cmd = parser.get_command();
+	zassert_true(cmd.has_value(), "Should parse GC command");
+	zassert_equal(cmd->family, CommandFamily::DateTime, "GC should be DateTime family");
+
+	// :GT# - Get tracking rate (uppercase G, not lowercase g)
+	parser.reset();
+	for (const char c : std::string_view(":GT#")) {
 		parser.feed_character(c);
 	}
 	cmd = parser.get_command();
+	zassert_true(cmd.has_value(), "Should parse GT command");
+	zassert_equal(cmd->family, CommandFamily::GetInfo, "GT should be GetInfo family");
+}
+
+/**
+ * @brief Test GPS command family (lowercase g)
+ * 
+ * NOTE: According to LX200CommandSet.md Appendix B.2:
+ * - :gT# is "Set Mount Time from GPS" (OAT/LX200GPS)
+ * - This is a BLOCKING call that attempts GPS sync for 2 minutes
+ * - Returns: 1 if data set, 0 if timeout
+ * - NOT the same as :GT# (Get tracking rate)
+ */
+ZTEST(lx200, test_gps_commands)
+{
+	ParserState parser;
+
+	// :gT# - Set mount time from GPS (lowercase g = GPS family)
+	for (const char c : std::string_view(":gT#")) {
+		parser.feed_character(c);
+	}
+	auto cmd = parser.get_command();
 	zassert_true(cmd.has_value(), "Should parse gT command");
-	zassert_equal(cmd->family, CommandFamily::GetInfo, "gT should be GetInfo family");
+	zassert_equal(cmd->family, CommandFamily::GPS, "gT should be GPS family");
+
+	// :gTnnn# - Set mount time from GPS with timeout [OAT Extension]
+	parser.reset();
+	for (const char c : std::string_view(":gT5000#")) {
+		parser.feed_character(c);
+	}
+	cmd = parser.get_command();
+	zassert_true(cmd.has_value(), "Should parse gTnnn command");
+	zassert_equal(cmd->family, CommandFamily::GPS, "gTnnn should be GPS family");
+	zassert_mem_equal(cmd->parameters.data(), "5000", 4, "Timeout parameter should be extracted");
+
+	// :g+# - Turn on GPS power [LX200GPS]
+	parser.reset();
+	for (const char c : std::string_view(":g+#")) {
+		parser.feed_character(c);
+	}
+	cmd = parser.get_command();
+	zassert_true(cmd.has_value(), "Should parse g+ command");
+	zassert_equal(cmd->family, CommandFamily::GPS, "g+ should be GPS family");
+
+	// :g-# - Turn off GPS power [LX200GPS]
+	parser.reset();
+	for (const char c : std::string_view(":g-#")) {
+		parser.feed_character(c);
+	}
+	cmd = parser.get_command();
+	zassert_true(cmd.has_value(), "Should parse g- command");
+	zassert_equal(cmd->family, CommandFamily::GPS, "g- should be GPS family");
 }
 
 /**
@@ -289,15 +348,58 @@ ZTEST(lx200, test_user_commands)
 }
 
 /**
- * @brief Test Library and GPS command families (X, W)
+ * @brief Test Library command family (L)
+ * 
+ * NOTE: Library commands for object selection (Messier, NGC, etc.)
+ * According to LX200CommandSet.md:
+ * - :LMNNNN# - Select Messier object
+ * - :LI# - Get object information
+ * - :LB# - Find previous object
+ * - :LN# - Find next object
  */
-ZTEST(lx200, test_library_gps_commands)
+ZTEST(lx200, test_library_commands)
 {
 	ParserState parser;
 
-	// Test Library command family would go here
-	// Test GPS command family would go here
-	// These are less common and may be implemented later
+	// :LI# - Get Object Information
+	for (const char c : std::string_view(":LI#")) {
+		parser.feed_character(c);
+	}
+	auto cmd = parser.get_command();
+	zassert_true(cmd.has_value(), "Should parse LI command");
+	zassert_equal(cmd->family, CommandFamily::Library, "LI should be Library family");
+
+	// :LMNNNN# - Set Messier object
+	parser.reset();
+	for (const char c : std::string_view(":LM0031#")) {
+		parser.feed_character(c);
+	}
+	cmd = parser.get_command();
+	zassert_true(cmd.has_value(), "Should parse LM command");
+	zassert_equal(cmd->family, CommandFamily::Library, "LM should be Library family");
+	zassert_mem_equal(cmd->parameters.data(), "0031", 4, "Messier number should be extracted");
+}
+
+/**
+ * @brief Test Extended OAT command family (X)
+ * 
+ * NOTE: According to LX200CommandSet.md Appendix B.9:
+ * - 50+ OAT-specific commands starting with :X
+ * - Used by OATControl PC application
+ * - Examples: :XFR# (factory reset), :XGM# (get mount config),
+ *   :XGB# (get backlash), :XSB# (set backlash), etc.
+ */
+ZTEST(lx200, test_extended_oat_commands)
+{
+	ParserState parser;
+
+	// :XFR# - Factory Reset [OAT Extension]
+	for (const char c : std::string_view(":XFR#")) {
+		parser.feed_character(c);
+	}
+	auto cmd = parser.get_command();
+	zassert_true(cmd.has_value(), "Should parse XFR command");
+	zassert_equal(cmd->family, CommandFamily::Extended, "XFR should be Extended family");
 }
 
 /**