Use pytest for tests.

tests/trace_service.py

@@ -0,0 +1,86 @@
+import concurrent
+import grpc
+from opentelemetry.proto.collector.trace.v1 import trace_service_pb2
+from opentelemetry.proto.collector.trace.v1 import trace_service_pb2_grpc
+import pytest
+import subprocess
+import time
+
+
+class TraceService(trace_service_pb2_grpc.TraceServiceServicer):
+    batches = []
+
+    def Export(self, request, context):
+        self.batches.append(request.resource_spans)
+        return trace_service_pb2.ExportTracePartialSuccess()
+
+    def get_span(self):
+        for _ in range(10):
+            if len(self.batches):
+                break
+            time.sleep(0.001)
+
+        assert len(self.batches) == 1, "No spans received"
+        span = self.batches[0][0].scope_spans[0].spans.pop()
+        self.batches.clear()
+        return span
+
+
+@pytest.fixture(scope="module")
+def trace_service(pytestconfig, logger):
+    server = grpc.server(concurrent.futures.ThreadPoolExecutor())
+    trace_service = TraceService()
+    trace_service_pb2_grpc.add_TraceServiceServicer_to_server(
+        trace_service, server
+    )
+    listen_addr = f"127.0.0.1:{24317 if pytestconfig.option.otelcol else 14317}"
+    server.add_insecure_port(listen_addr)
+    logger.info(f"Starting trace service at {listen_addr}...")
+    server.start()
+    yield trace_service
+    logger.info("Stopping trace service...")
+    server.stop(grace=None)
+
+
+@pytest.fixture(scope="module")
+def otelcol(pytestconfig, testdir, logger, trace_service):
+    if pytestconfig.option.otelcol is None:
+        yield
+        return
+
+    (testdir / "otel-config.yaml").write_text(
+        """receivers:
+  otlp:
+    protocols:
+      grpc:
+        endpoint: 127.0.0.1:14317
+
+exporters:
+  otlp:
+    endpoint: 127.0.0.1:24317
+    tls:
+      insecure: true
+
+service:
+  pipelines:
+    traces:
+      receivers: [otlp]
+      exporters: [otlp]
+  telemetry:
+    metrics:
+      # prevent otelcol from opening 8888 port
+      level: none"""
+    )
+    logger.info("Starting otelcol at 127.0.0.1:14317...")
+    proc = subprocess.Popen(
+        [pytestconfig.option.otelcol, "--config", testdir / "otel-config.yaml"]
+    )
+    time.sleep(1)  # give some time to get ready
+    assert proc.poll() is None, "Can't start otelcol"
+    yield
+    logger.info("Stopping otelcol...")
+    proc.terminate()
+    try:
+        proc.wait(timeout=5)
+    except subprocess.TimeoutExpired:
+        proc.kill()