diff --git a/tests/run_test.sh b/tests/run_test.sh
index 89daa71f..b8fe0fbe 100755
--- a/tests/run_test.sh
+++ b/tests/run_test.sh
@@ -1,46 +1,41 @@
 #!/bin/bash
-# Setup and run the layer test on B200 — no Docker, no vLLM
-# Compiles the kernel raw and runs the comparison test
+# Test harness: runs a test in screen, logs to kernel-test.log
+# Usage: ./run_test.sh <test_file>
+# Example: ./run_test.sh tests/unit/test_fmha_v3.py
 
-set -euo pipefail
+set -e
 
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-REPO_DIR="$(dirname "$SCRIPT_DIR")"
-VENV_DIR="$REPO_DIR/tests/.venv"
+TEST_FILE="${1:?Usage: $0 <test_file>"
 
-echo "=== NVFP4 Layer Test Setup ==="
-echo "Repo: $REPO_DIR"
-echo ""
-
-# 1. Create venv
-if [ ! -d "$VENV_DIR" ]; then
-    echo "[1/4] Creating venv..."
-    python3 -m venv "$VENV_DIR"
-else
-    echo "[1/4] Venv already exists, skipping"
+# --- CLEANUP ---
+# Kill existing screen and all its processes
+if screen -list | grep -q kernel-test; then
+    echo "Killing existing kernel-test screen..."
+    screen -S kernel-test -X quit 2>/dev/null || true
+    sleep 2
+    # Nuclear option: kill any lingering python test processes
+    pkill -f "python.*test_fmha" 2>/dev/null || true
+    sleep 1
 fi
 
-source "$VENV_DIR/bin/activate"
+# Remove old log
+rm -f /tmp/kernel-test.log
 
-# 2. Install dependencies
-echo "[2/4] Installing Python deps..."
-pip install --upgrade pip -q
-pip install -r "$SCRIPT_DIR/requirements.txt" -q
+# --- START ---
+cd /root/dsv4-nvfp4-workspace/kernel
+source /root/dsv4-nvfp4-workspace/venv/bin/activate
+export PYTHONPATH=/root/dsv4-nvfp4-workspace/kernel
 
-# 3. Build and install the kernel from source
-echo "[3/4] Building kernel from source (this takes a few minutes)..."
-cd "$REPO_DIR"
-pip install -e . --no-build-isolation -q
+echo "Running: python -u $TEST_FILE"
+echo "Log: /tmp/kernel-test.log"
+screen -dmS kernel-test bash -c "python -u $TEST_FILE > /tmp/kernel-test.log 2>&1"
+sleep 2
 
-# Build the CUTLASS NVFP4 GEMM C++ extension
-echo "       Building CUTLASS C++ extension..."
-cd "$REPO_DIR/src/nvfp4_megamoe_kernel/cutlass_nvfp4_gemm"
-python setup.py install
-
-# 4. Run the test
-echo "[4/4] Running layer test..."
-cd "$SCRIPT_DIR"
-python3 layertest.py
-
-echo ""
-echo "=== Done ==="
+# Verify it started
+if screen -list | grep -q kernel-test; then
+    echo "OK: screen 'kernel-test' is running"
+else
+    echo "FAIL: screen did not start. Check /tmp/kernel-test.log"
+    cat /tmp/kernel-test.log 2>/dev/null
+    exit 1
+fi