feat: add testing framework with reference project integration

- Add test/ directory with test harness and test files
- Add UDT, DB, FB parser tests
- Add PLC JSON and integration tests
- Test against reference project (239 UDTs, 12 DBs, 37 SCL, 13 XML)
- Fix attribute parsing to handle underscores (S7_SetPoint)
- Add ORGANIZATION_BLOCK support to FB parser

test/test_harness.lua

@@ -0,0 +1,168 @@
+local M = {}
+
+M.test_count = 0
+M.pass_count = 0
+M.fail_count = 0
+M.failures = {}
+
+M.REF_PROJECT = os.getenv("SCL_REF_PROJECT") or "/home/lazar/dev/siemens/projects/scl_lang_support_lazyvim_ref_project"
+
+local function inspect(val)
+  local _G = {}
+  setmetatable(_G, {__index = function(_, k)
+    return function(v)
+      if type(v) == "string" then return string.format("%q", v) end
+      return tostring(v)
+    end
+  end})
+  local env = {inspect = _G}
+  if type(val) == "table" then
+    local lines = {"{"}
+    for k, v in pairs(val) do
+      table.insert(lines, string.format("  [%s] = %s,", inspect(k), inspect(v)))
+    end
+    table.insert(lines, "}")
+    return table.concat(lines, "\n")
+  elseif type(val) == "string" then
+    return string.format("%q", val)
+  else
+    return tostring(val)
+  end
+end
+
+function M.assert(condition, message)
+  M.test_count = M.test_count + 1
+  if condition then
+    M.pass_count = M.pass_count + 1
+    return true
+  else
+    M.fail_count = M.fail_count + 1
+    table.insert(M.failures, {
+      test = message or "unnamed test",
+      msg = "assertion failed"
+    })
+    return false
+  end
+end
+
+function M.assert_equals(actual, expected, message)
+  M.test_count = M.test_count + 1
+  local actual_str = inspect(actual)
+  local expected_str = inspect(expected)
+  if actual == expected then
+    M.pass_count = M.pass_count + 1
+    return true
+  else
+    M.fail_count = M.fail_count + 1
+    table.insert(M.failures, {
+      test = message or "assert_equals",
+      msg = string.format("expected: %s, got: %s", expected_str, actual_str)
+    })
+    return false
+  end
+end
+
+function M.assert_not_nil(value, message)
+  M.test_count = M.test_count + 1
+  if value ~= nil then
+    M.pass_count = M.pass_count + 1
+    return true
+  else
+    M.fail_count = M.fail_count + 1
+    table.insert(M.failures, {
+      test = message or "assert_not_nil",
+      msg = "value is nil"
+    })
+    return false
+  end
+end
+
+function M.assert_nil(value, message)
+  M.test_count = M.test_count + 1
+  if value == nil then
+    M.pass_count = M.pass_count + 1
+    return true
+  else
+    M.fail_count = M.fail_count + 1
+    table.insert(M.failures, {
+      test = message or "assert_nil",
+      msg = string.format("expected nil, got: %s", inspect(value))
+    })
+    return false
+  end
+end
+
+function M.assert_gt(actual, expected, message)
+  M.test_count = M.test_count + 1
+  if actual > expected then
+    M.pass_count = M.pass_count + 1
+    return true
+  else
+    M.fail_count = M.fail_count + 1
+    table.insert(M.failures, {
+      test = message or "assert_gt",
+      msg = string.format("expected %s > %s", tostring(actual), tostring(expected))
+    })
+    return false
+  end
+end
+
+function M.assert_items_equal(actual, expected, message)
+  M.test_count = M.test_count + 1
+  if not actual or not expected then
+    M.fail_count = M.fail_count + 1
+    table.insert(M.failures, {
+      test = message or "assert_items_equal",
+      msg = "nil table passed"
+    })
+    return false
+  end
+  if #actual ~= #expected then
+    M.fail_count = M.fail_count + 1
+    table.insert(M.failures, {
+      test = message or "assert_items_equal",
+      msg = string.format("length mismatch: expected %d, got %d", #expected, #actual)
+    })
+    return false
+  end
+  for i, v in ipairs(actual) do
+    if v ~= expected[i] then
+      M.fail_count = M.fail_count + 1
+      table.insert(M.failures, {
+        test = message or "assert_items_equal",
+        msg = string.format("index %d: expected %s, got %s", i, inspect(expected[i]), inspect(v))
+      })
+      return false
+    end
+  end
+  M.pass_count = M.pass_count + 1
+  return true
+end
+
+function M.reset()
+  M.test_count = 0
+  M.pass_count = 0
+  M.fail_count = 0
+  M.failures = {}
+end
+
+function M.report()
+  print(string.format("\n=== Test Results ==="))
+  print(string.format("Total: %d | Passed: %d | Failed: %d", M.test_count, M.pass_count, M.fail_count))
+  if M.fail_count > 0 then
+    print("\nFailures:")
+    for _, f in ipairs(M.failures) do
+      print(string.format("  - %s: %s", f.test, f.msg))
+    end
+  end
+  return M.fail_count == 0
+end
+
+function M.run_suite(name, fn)
+  print(string.format("\n=== Running %s ===", name))
+  M.reset()
+  fn()
+  M.report()
+end
+
+return M