Add DebuggerTests test suite

Author: MaxDesiatov

Sources/WasmKit/Execution/Debugger.swift

@@ -1,7 +1,7 @@
 #if WasmDebuggingSupport
 
     package struct Debugger: ~Copyable {
-        enum Error: Swift.Error {
+        package enum Error: Swift.Error {
             case entrypointFunctionNotFound
             case noInstructionMappingAvailable(Int)
         }
@@ -59,8 +59,9 @@
             }
         }
 
-        package mutating func enableBreakpoint(address: Int) throws {
+        package mutating func enableBreakpoint(address: Int) throws(Error) {
             print("attempt to toggle a breakpoint at \(address)")
+            print("available mapping: \(self.instance.handle.wasmToIseqMapping)")
 
             guard self.breakpoints[address] == nil else {
                 print("breakpoint at \(address) already enabled")
@@ -74,7 +75,7 @@
             iseq.pointee = Instruction.breakpoint.headSlot(threadingModel: self.threadingModel)
         }
 
-        package mutating func disableBreakpoint(address: Int) throws {
+        package mutating func disableBreakpoint(address: Int) throws(Error) {
             print("attempt to toggle a breakpoint at \(address)")
 
             guard let oldCodeSlot = self.breakpoints[address] else {
@@ -85,11 +86,12 @@
             guard let iseq = self.instance.handle.wasmToIseqMapping[address] else {
                 throw Error.noInstructionMappingAvailable(address)
             }
-            iseq.pointee = oldCodeSlot
             self.breakpoints[address] = nil
+            iseq.pointee = oldCodeSlot
         }
 
-        mutating func enableBreakpoint(functionIndex: FunctionIndex, offset: Int) {
+        package func run() throws {
+            try self.entrypointFunction()
         }
 
         /// Array of addresses in the Wasm binary of executed instructions on the call stack.

Sources/WasmKit/Execution/Errors.swift

@@ -16,8 +16,7 @@ struct Backtrace: CustomStringConvertible, Sendable {
 
     /// Textual description of the backtrace.
     var description: String {
-        print("backtrace contains \(symbols.count) symbols")
-        return symbols.enumerated().map { (index, symbol) in
+        symbols.enumerated().map { (index, symbol) in
             let name = symbol.name ?? "unknown"
             return "    \(index): (\(symbol.address)) \(name)"
         }.joined(separator: "\n")

Tests/WasmKitTests/DebuggerTests.swift

@@ -0,0 +1,38 @@
+#if WasmDebuggingSupport
+
+import Testing
+import WAT
+@testable import WasmKit
+
+private let trivialModuleWAT = """
+(module
+    (func (export "_start") (result i32) (local $x i32)
+        (i32.const 42)
+        (i32.const 0)
+        (i32.eqz)
+        (drop)
+        (local.set $x)
+        (local.get $x)
+    )
+)
+"""
+
+@Suite
+struct DebuggerTests {
+    @Test
+    func stopAtEntrypoint() throws {
+        let store = Store(engine: Engine())
+        let bytes = try wat2wasm(trivialModuleWAT)
+        print(bytes.count)
+        let module = try parseWasm(bytes: bytes)
+        var debugger = try Debugger(module: module, store: store, imports: [:])
+
+        try debugger.stopAtEntrypoint()
+
+        #expect(throws: Execution.Breakpoint.self) {
+            try debugger.run()
+        }
+    }
+}
+
+#endif