test(docker-tests): add end-to-end test for file-based declarative configuration

tests/opentelemetry-docker-tests/tests/declarative_config/minimal_config.yaml

@@ -0,0 +1,12 @@
+file_format: "1.0"
+disabled: false
+resource:
+  attributes:
+    - name: "service.name"
+      value: "e2e-docker-test-service"
+tracer_provider:
+  processors:
+    - batch:
+        exporter:
+          otlp:
+            endpoint: "http://localhost:4317"

tests/opentelemetry-docker-tests/tests/declarative_config/test_otel_config_file.py

@@ -0,0 +1,27 @@
+import os
+from opentelemetry import trace
+from opentelemetry.sdk._configuration import _OTelSDKConfigurator
+
+def test_otel_config_file_e2e(monkeypatch):
+    """
+    Validates that setting OTEL_CONFIG_FILE properly instantiates the SDK
+    and exports a trace directly to the running Docker collector backend.
+    """
+    config_path = os.path.join(os.path.dirname(__file__), "minimal_config.yaml")
+
+    # Safely inject the configuration path environment variable into this process
+    monkeypatch.setenv("OTEL_CONFIG_FILE", config_path)
+
+    # Force the configuration setup to read our new config file path
+    _OTelSDKConfigurator()._configure()
+
+    # Get the configurator-initialized tracer provider and tracer instances
+    provider = trace.get_tracer_provider()
+    tracer = trace.get_tracer("e2e-test")
+
+    # Emit a span directly to confirm no trace piping exceptions occur
+    with tracer.start_as_current_span("docker-plumbing-span"):
+        print("\nSpan emitted successfully via inline configuration parsing!")
+
+    # Explicitly flush and close the pipeline so data hits the collector before python exits
+    provider.shutdown()