diff --git a/cwltest/__init__.py b/cwltest/__init__.py
index f89f413..5a63b77 100755
--- a/cwltest/__init__.py
+++ b/cwltest/__init__.py
@@ -470,9 +470,17 @@ def main():  # type: () -> int
 
     for t in tests:
         if t.get("label"):
+            _logger.warning("The `label` field is deprecated. Use `id` field instead.")
             t["short_name"] = t["label"]
-        elif t.get("id") and isinstance(t.get("id"), str):
-            t["short_name"] = shortname(t["id"])
+        elif t.get("id"):
+            if isinstance(t.get("id"), str):
+                t["short_name"] = shortname(t["id"])
+            else:
+                _logger.warning(
+                    "The `id` field with integer is deprecated. Use string identifier instead."
+                )
+        else:
+            _logger.warning("The `id` field is missing.")
 
     if args.show_tags:
         alltags = set()  # type: Set[str]
diff --git a/cwltest/tests/test-data/integer-id.yml b/cwltest/tests/test-data/integer-id.yml
new file mode 100644
index 0000000..8223cef
--- /dev/null
+++ b/cwltest/tests/test-data/integer-id.yml
@@ -0,0 +1,5 @@
+- job: v1.0/cat1-job.json
+  output: {}
+  tool: return-0.cwl
+  doc: Test with an integer id
+  id: 1
diff --git a/cwltest/tests/test_categories.py b/cwltest/tests/test_categories.py
index 77e8711..9da4e30 100644
--- a/cwltest/tests/test_categories.py
+++ b/cwltest/tests/test_categories.py
@@ -31,6 +31,8 @@ def test_unsupported_with_required_tests():
     else:
         q = ""
     assert (
+        "The `id` field is missing.{n}"
+        "The `id` field is missing.{n}"
         "Test [1/2] Required test that is unsupported (without tags){n}"
         "{n}"
         "Test 1 failed: mock-cwl-runner --quiet return-unsupported.cwl {q}v1.0{p}cat-job.json{q}{n}"
@@ -57,6 +59,7 @@ def test_unsupported_with_optional_tests():
     error_code, stdout, stderr = run_with_mock_cwl_runner(args)
     assert error_code == 0
     assert (
+        "The `id` field is missing.{n}"
         "Test [1/1] Optional test that is unsupported{n}{n}"
         "0 tests passed, 1 unsupported "
         "features{n}".format(n=n)
diff --git a/cwltest/tests/test_integer_id.py b/cwltest/tests/test_integer_id.py
new file mode 100644
index 0000000..7993111
--- /dev/null
+++ b/cwltest/tests/test_integer_id.py
@@ -0,0 +1,19 @@
+import os
+from os import linesep as n
+from pathlib import Path
+
+from .util import run_with_mock_cwl_runner, get_data
+import defusedxml.ElementTree as ET
+
+
+def test_warning_with_integer_id():
+    args = [
+        "--test",
+        get_data("tests/test-data/integer-id.yml"),
+        "-l",
+    ]
+    error_code, stdout, stderr = run_with_mock_cwl_runner(args)
+    assert (
+        "The `id` field with integer is deprecated. Use string identifier instead."
+        in stderr
+    )
diff --git a/cwltest/tests/test_multi_lined_doc.py b/cwltest/tests/test_multi_lined_doc.py
index 1fa1501..9b6f4b3 100644
--- a/cwltest/tests/test_multi_lined_doc.py
+++ b/cwltest/tests/test_multi_lined_doc.py
@@ -9,6 +9,7 @@
 def test_run():
     args = ["--test", get_data("tests/test-data/multi-lined-doc.yml")]
     error_code, stdout, stderr = run_with_mock_cwl_runner(args)
+    assert "The `label` field is deprecated. Use `id` field instead." in stderr
     assert f"Test [1/2] opt-error: Test with label{n}" in stderr
     assert f"Test [2/2] Test without label{n}" in stderr