Continue converting tests to the Lua spec framework

 - Remove Lua 5.2 bitwise test - this already exists at bit32_spec.

 - Port Lua 5.1 to 5.4's strings.lua. This has highlighted several
   issues with Cobalt here, which I'm leaving to fix in a separate
   commit. It's not entirely clear what the correct behaviour is in all
   cases.

 - Port a couple of our general "assert" tests.

src/main/java/org/squiddev/cobalt/lib/FormatDesc.java

@@ -50,7 +50,7 @@ public class FormatDesc {
 
 	private final int flags;
 	private final int width;
-	final int precision;
+	private final int precision;
 
 	final int conversion;
 
@@ -159,7 +159,10 @@ void checkFlags(int flags) throws LuaError {
 	}
 
 	void format(Buffer buf, byte c) {
+		int nSpaces = width > 1 ? width - 1 : 0;
+		if (!leftAdjust()) pad(buf, ' ', nSpaces);
 		buf.append(c);
+		if (leftAdjust()) pad(buf, ' ', nSpaces);
 	}
 
 	public void format(Buffer buf, long number) {

src/main/java/org/squiddev/cobalt/lib/StringFormat.java

@@ -96,7 +96,7 @@ static LuaString format(LuaState state, FormatState format) throws LuaError, Unw
 					desc.format(result, value.checkDouble());
 				}
 				case 'q' -> {
-					desc.checkFlags(0);
+					if (desc.length != 1) throw new LuaError("specifier '%q' cannot have modifiers");
 					addQuoted(result, format.arg, value);
 				}
 				case 's' -> {
@@ -139,7 +139,7 @@ private static void addQuoted(Buffer buf, int arg, LuaValue s) throws LuaError {
 				}
 			}
 			case TBOOLEAN, TNIL -> buf.append(s.toString());
-			default -> throw ErrorFactory.argError(arg, "value has no literal representation");
+			default -> throw ErrorFactory.argError(arg, "value has no literal form");
 		}
 	}
 

src/test/java/org/squiddev/cobalt/AssertTests.java

@@ -52,20 +52,15 @@ public void tables(String name) throws IOException, CompileException, LuaError,
 	@ParameterizedTest(name = ParameterizedTest.ARGUMENTS_WITH_NAMES_PLACEHOLDER)
 	@ValueSource(strings = {
 		"debug",
-		"debug-coroutine-hook",
 		"debug-getinfo",
 		"debug-upvalue",
 		"gc",
 		"immutable",
 		"invalid-tailcall",
 		"lex-context",
 		"lex-number",
-		"load-error",
-		"no-unwind",
 		"setlist",
-		"string-compare",
 		"string-issues",
-		"string-format",
 		"time",
 		"traceback",
 	})
@@ -95,7 +90,6 @@ public void main(String name) throws IOException, CompileException, LuaError, In
 		"nextvar",
 		"pm",
 		"sort",
-		"strings",
 		"vararg",
 		"verybig",
 	})
@@ -113,19 +107,6 @@ public void lua51(String name) throws Exception {
 		helpers.runWithDump(name);
 	}
 
-	@ParameterizedTest(name = ParameterizedTest.ARGUMENTS_WITH_NAMES_PLACEHOLDER)
-	@ValueSource(strings = {
-		"bitwise",
-		"strings",
-	})
-	public void lua52(String name) throws Exception {
-		ScriptHelper helpers = new ScriptHelper("/assert/lua5.2/");
-		helpers.setup(x -> x.bytecodeFormat(LuaBytecodeFormat.instance()));
-		Bit32Lib.add(helpers.state, helpers.globals);
-
-		helpers.runWithDump(name);
-	}
-
 	@ParameterizedTest(name = ParameterizedTest.ARGUMENTS_WITH_NAMES_PLACEHOLDER)
 	@ValueSource(strings = {
 		"db",

src/test/java/org/squiddev/cobalt/LuaSpecTest.java

@@ -89,11 +89,13 @@ public LuaSpecTest() throws IOException, LuaError, CompileException {
 
 		env.rawset("fail", RegisteredFunction.of("fail", (state, arg) -> {
 			var frame = state.getCurrentThread().getDebugState().getFrame(2);
-			var values = frame.stack;
-			for (int i = 0; i < values.length; i++) {
-				var value = values[i];
-				var local = frame.closure.getPrototype().getLocalName(i + 1, frame.pc);
-				if (!value.isNil() || local != null) System.out.printf("% 2d => %s [%s]\n", i, values[i], local);
+			if (frame != null && frame.stack != null) {
+				var values = frame.stack;
+				for (int i = 0; i < values.length; i++) {
+					var value = values[i];
+					var local = frame.closure.getPrototype().getLocalName(i + 1, frame.pc);
+					if (!value.isNil() || local != null) System.out.printf("% 2d => %s [%s]\n", i, values[i], local);
+				}
 			}
 			throw new AssertionError(arg.checkString() + "\n" + DebugHelpers.traceback(state.getCurrentThread(), 0));
 		}).create());
@@ -127,7 +129,7 @@ private static DynamicNode makePending(DynamicNode node) {
 	public Stream<DynamicNode> getTests() throws IOException {
 		return Files.walk(ROOT)
 			.filter(x -> x.getFileName().toString().endsWith("_spec.lua"))
-			.map(path -> {
+			.flatMap(path -> {
 				LuaFunction function;
 				try (InputStream stream = Files.newInputStream(path)) {
 					function = LoadState.load(state, stream, "@" + path.getFileName(), env);
@@ -144,7 +146,7 @@ public Stream<DynamicNode> getTests() throws IOException {
 					this.nodes = null;
 				}
 
-				return DynamicContainer.dynamicContainer(path.getFileName().toString(), nodes);
+				return nodes.stream();
 			});
 	}
 }