diff --git a/src/manip/DebugAdapter.test.scala b/src/manip/DebugAdapter.test.scala
new file mode 100644
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+++ b/src/manip/DebugAdapter.test.scala
@@ -0,0 +1,253 @@
+// Copyright 2024-2025 Forja Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package forja.manip
+
+import java.net.{InetSocketAddress, Socket}
+import java.nio.charset.StandardCharsets
+import java.util.concurrent.LinkedBlockingQueue
+
+import forja.*
+import forja.dsl.*
+import forja.langs.tla.{TLAParser, TLAReader}
+import forja.source.{Source, SourceRange}
+
+import scala.collection.mutable
+import scala.compiletime.uninitialized
+
+class DebugAdapterTests extends munit.FunSuite:
+  case class DAPMessage(
+      messageType: String,
+      content: String,
+      timestamp: Long = System.currentTimeMillis(),
+  )
+
+  class DAPClient(host: String, port: Int) extends AutoCloseable:
+    private val socket: Socket = Socket()
+    private var seqNum = 1
+    private val asyncQueue = new LinkedBlockingQueue[DAPMessage]()
+    @volatile private var running = false
+    private var readerThread: Thread = uninitialized
+
+    def connect(): Unit =
+      socket.connect(InetSocketAddress(host, port), 5000)
+      running = true
+      readerThread = new Thread(
+        () => {
+          try {
+            while (running && !socket.isClosed) {
+              val msg = readResponse()
+              asyncQueue.put(msg)
+            }
+          } catch {
+            case _: java.io.EOFException | _: java.net.SocketTimeoutException |
+                _: ujson.IncompleteParseException =>
+            // Normal shutdown
+            case ex: Exception =>
+              println(s"[DAPClient] Reader thread exception: $ex")
+          }
+        },
+        "dap-client-reader",
+      )
+      readerThread.setDaemon(true)
+      readerThread.start()
+
+    def close(): Unit =
+      running = false
+      if ((readerThread: AnyRef) ne null) readerThread.interrupt()
+      socket.close()
+
+    def sendRequest(command: String, args: ujson.Value = ujson.Obj()): Unit =
+      val requestObj = ujson.Obj(
+        "seq" -> seqNum,
+        "type" -> "request",
+        "command" -> command,
+        "arguments" -> args,
+      )
+      val payloadBytes = ujson.writeToByteArray(requestObj)
+      socket.getOutputStream.write(
+        s"Content-Length: ${payloadBytes.length}\r\n\r\n"
+          .getBytes(StandardCharsets.UTF_8),
+      )
+      socket.getOutputStream.write(payloadBytes)
+      seqNum += 1
+
+    def takeNMessages(n: Int): Seq[DAPMessage] =
+      val messages = mutable.Buffer[DAPMessage]()
+      var count = 0
+      while count < n do
+        val msg = asyncQueue.take()
+        if msg != null then
+          messages += msg
+          count += 1
+      messages.toSeq
+
+    private def readResponse(): DAPMessage =
+      val input = socket.getInputStream
+      val buffer = StringBuilder()
+      var contentLength = -1
+
+      while contentLength == -1 do
+        val read = input.read()
+        if read == -1 then
+          // If nothing was read, treat as normal shutdown, not a protocol error
+          socket.close()
+          if buffer.isEmpty then
+            throw new java.io.EOFException(
+              "Socket closed while reading headers (empty buffer)",
+            )
+          else
+            // Only fail if there was partial, non-header data
+            fail(
+              "Socket closed with partial, non-header data: " + buffer.toString,
+            )
+        val char = read.toChar
+        buffer.append(char)
+        if buffer.toString.endsWith("\r\n\r\n") then
+          val headers = buffer.toString
+          headers match
+            case s if s.contains("Content-Length:") =>
+              val lengthPattern = """Content-Length: (\d+)""".r
+              lengthPattern.findFirstMatchIn(headers) match
+                case Some(m) => contentLength = m.group(1).toInt
+                case None =>
+                  socket.close()
+                  fail("Malformed DAP header: Content-Length not found")
+            case _ =>
+              socket.close()
+              fail("Malformed DAP header: Content-Length not found")
+
+      val jsonBytes = Array.ofDim[Byte](contentLength)
+      val bytesRead = input.readNBytes(jsonBytes, 0, contentLength)
+      if bytesRead != contentLength then
+        socket.close()
+        fail(s"Expected $contentLength bytes, got $bytesRead")
+      val json = String(jsonBytes, StandardCharsets.UTF_8)
+
+      val js = ujson.read(json)
+      val messageType =
+        js.obj.get("type").map(_.str) match
+          case Some("response") => "response"
+          case Some("event")    => "event"
+          case _                => "unknown"
+
+      val dapMessage = DAPMessage(messageType, json)
+      dapMessage
+
+  val debugAdapterFixture = FunFixture[DebugAdapter](
+    setup = { _ =>
+      val host = "localhost"
+      val port = 4711
+      val adapter = DebugAdapter(host, port)
+      Thread.sleep(1000)
+      adapter
+    },
+    teardown = { adapter =>
+      adapter.close()
+    },
+  )
+
+  def createTestTLASource(): Source =
+    val tlaContent = """
+                       |---- MODULE TestModule ----
+                       |EXTENDS Naturals
+                       |
+                       |VARIABLE x
+                       |
+                       |Init == x = 0
+                       |
+                       |Next == x' = x + 1
+                       |
+                       |Spec == Init /\ [][Next]_x
+                       |
+                       |====
+    """.stripMargin
+
+    Source.fromString(tlaContent)
+
+  debugAdapterFixture.test(
+    "handles Step Over request with actual compiler execution",
+  ) { debugAdapter =>
+    val client = DAPClient("localhost", 4711)
+    try {
+      client.connect()
+
+      val compilerThread = new Thread(() => {
+        val src = createTestTLASource()
+        val top = TLAReader(SourceRange.entire(src))
+        instrumentWithTracer(debugAdapter) {
+          TLAParser(top)
+        }
+      })
+
+      compilerThread.start()
+
+      // Send all requests up front, without blocking for responses
+      client.sendRequest(
+        "initialize",
+        ujson.Obj(
+          "clientID" -> "test",
+          "adapterID" -> "forja",
+        ),
+      )
+      var messages = client.takeNMessages(1)
+      assert(messages.nonEmpty, "Expected an initialize response")
+      assert(
+        messages.exists(_.messageType == "response"),
+        "Expected an initialize response",
+      )
+      println(s"${messages(0).messageType}: ${messages(0).content}\n")
+
+      client.sendRequest("attach")
+      messages = client.takeNMessages(2)
+      assert(messages.nonEmpty, "Expected an initialize response")
+      assert(
+        messages.exists(_.messageType == "response"),
+        "Expected an attach response",
+      )
+      println(s"${messages(0).messageType}: ${messages(0).content}")
+      assert(messages.exists(_.messageType == "event"), "Expected a next event")
+      println(s"${messages(1).messageType}: ${messages(1).content}\n")
+
+      client.sendRequest("next", ujson.Obj("threadId" -> 1))
+      messages = client.takeNMessages(3)
+      assert(messages.nonEmpty, "Expected a next response")
+      assert(
+        messages.exists(_.messageType == "response"),
+        "Expected a next response",
+      )
+      println(s"${messages(0).messageType}: ${messages(0).content}")
+      assert(
+        messages.exists(_.messageType == "event"),
+        "Expected a loadedSource event",
+      )
+      println(s"${messages(1).messageType}: ${messages(1).content}")
+      assert(
+        messages.exists(_.messageType == "event"),
+        "Expected a stopped event",
+      )
+      println(s"${messages(2).messageType}: ${messages(2).content}\n")
+
+      client.sendRequest("continue", ujson.Obj("threadId" -> 1))
+      messages = client.takeNMessages(1)
+      assert(messages.nonEmpty, "Expected a continue response")
+      println(s"${messages(0).messageType}: ${messages(0).content}\n")
+
+      println("Successfully got all expected DAP messages")
+
+      compilerThread.join()
+    } finally {
+      client.close()
+    }
+  }