NDMC-284: Add integration tests for snmp device discovery

[alpatriciodd]

What does this PR do?

Adds integration tests for the SNMP listener's device discovery flow. To make the listener testable without real SNMP devices, this introduces a snmpSession interface and session factory that the listener uses instead of calling gosnmp directly. Tests use fake sessions to test out different autodiscovery scenarios.

Motivation

The SNMP listener had no tests covering the end-to-end discovery flow. Existing tests only covered config parsing, subnet iteration, and caching. The tight coupling to gosnmp made it impossible to test discovery logic without a real SNMP device on the network.

Describe how you validated your changes

• Tests pass as expected
• Running locally and on staging works as usual

Additional Notes

• No changelog was added since no behavioral changes are expected for this PR.

[agent-platform-auto-pr]

Files inventory check summary

File checks results against ancestor de7acb4f:

Results for datadog-agent_7.79.0~devel.git.340.e29baff.pipeline.105473026-1_amd64.deb:

No change detected

[agent-platform-auto-pr]

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor de7acb4
📊 Static Quality Gates Dashboard
🔗 SQG Job

Error

	Quality gate	Change	Size (prev → curr → max)
⚠️	iot_agent_rpm_amd64 (on disk)	neutral	43.290 MiB → 43.290
⚠️	iot_agent_suse_amd64 (on disk)	neutral	43.290 MiB → 43.290

Gate failure full details

Quality gate	Error type	Error message
iot_agent_rpm_amd64	StaticQualityGateFailed (non-blocking: size unchanged from ancestor)	static_quality_gate_iot_agent_rpm_amd64 failed! Disk size 43.3 MB exceeds limit of 43.3 MB by 0.4 KB
iot_agent_suse_amd64	StaticQualityGateFailed (non-blocking: size unchanged from ancestor)	static_quality_gate_iot_agent_suse_amd64 failed! Disk size 43.3 MB exceeds limit of 43.3 MB by 0.4 KB

Note: Some gates exceeded limits but are non-blocking because the size hasn't increased from the ancestor commit.

Successful checks

Info

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64_fips	+8.0 KiB (0.00% increase)	709.979 → 709.987 → 713.900
✅	agent_heroku_amd64	+4.0 KiB (0.00% increase)	313.282 → 313.285 → 320.580
✅	agent_rpm_amd64_fips	+8.0 KiB (0.00% increase)	709.963 → 709.971 → 713.880
✅	agent_suse_amd64_fips	+8.0 KiB (0.00% increase)	709.963 → 709.971 → 713.880
✅	docker_cluster_agent_amd64	+8.0 KiB (0.00% increase)	203.917 → 203.924 → 206.270
✅	iot_agent_deb_arm64	+4.0 KiB (0.01% increase)	40.337 → 40.341 → 40.920
✅	iot_agent_deb_armhf	+4.0 KiB (0.01% increase)	41.084 → 41.088 → 41.100

21 successful checks with minimal change (< 2 KiB)

	Quality gate	Current Size
✅	agent_deb_amd64	753.048 MiB
✅	agent_rpm_amd64	753.031 MiB
✅	agent_rpm_arm64	731.452 MiB
✅	agent_rpm_arm64_fips	691.408 MiB
✅	agent_suse_amd64	753.031 MiB
✅	agent_suse_arm64	731.452 MiB
✅	agent_suse_arm64_fips	691.408 MiB
✅	docker_agent_amd64	813.351 MiB
✅	docker_agent_arm64	816.541 MiB
✅	docker_agent_jmx_amd64	1004.266 MiB
✅	docker_agent_jmx_arm64	996.235 MiB
✅	docker_cluster_agent_arm64	218.356 MiB
✅	docker_cws_instrumentation_amd64	7.142 MiB
✅	docker_cws_instrumentation_arm64	6.689 MiB
✅	docker_dogstatsd_amd64	39.234 MiB
✅	docker_dogstatsd_arm64	37.445 MiB
✅	dogstatsd_deb_amd64	29.878 MiB
✅	dogstatsd_deb_arm64	28.031 MiB
✅	dogstatsd_rpm_amd64	29.878 MiB
✅	dogstatsd_suse_amd64	29.878 MiB
✅	iot_agent_deb_amd64	43.290 MiB

On-wire sizes (compressed)

	Quality gate	Change	Size (prev → curr → max)
⚠️	iot_agent_rpm_amd64	neutral	11.421 MiB → 12.060
⚠️	iot_agent_suse_amd64	neutral	11.421 MiB → 12.060
✅	agent_deb_amd64	+36.69 KiB (0.02% increase)	174.737 → 174.773 → 178.360
✅	agent_deb_amd64_fips	-38.07 KiB (0.02% reduction)	165.379 → 165.342 → 172.790
✅	agent_heroku_amd64	neutral	74.994 MiB → 79.970
✅	agent_rpm_amd64	neutral	177.642 MiB → 181.830
✅	agent_rpm_amd64_fips	-31.5 KiB (0.02% reduction)	167.668 → 167.637 → 173.370
✅	agent_rpm_arm64	+45.11 KiB (0.03% increase)	159.510 → 159.554 → 163.060
✅	agent_rpm_arm64_fips	neutral	151.407 MiB → 156.170
✅	agent_suse_amd64	neutral	177.642 MiB → 181.830
✅	agent_suse_amd64_fips	-31.5 KiB (0.02% reduction)	167.668 → 167.637 → 173.370
✅	agent_suse_arm64	+45.11 KiB (0.03% increase)	159.510 → 159.554 → 163.060
✅	agent_suse_arm64_fips	neutral	151.407 MiB → 156.170
✅	docker_agent_amd64	+5.05 KiB (0.00% increase)	268.175 → 268.180 → 272.480
✅	docker_agent_arm64	+3.74 KiB (0.00% increase)	255.368 → 255.372 → 261.060
✅	docker_agent_jmx_amd64	neutral	336.826 MiB → 341.100
✅	docker_agent_jmx_arm64	neutral	320.008 MiB → 325.620
✅	docker_cluster_agent_amd64	neutral	71.362 MiB → 72.920
✅	docker_cluster_agent_arm64	-5.58 KiB (0.01% reduction)	66.989 → 66.983 → 68.220
✅	docker_cws_instrumentation_amd64	neutral	2.999 MiB → 3.330
✅	docker_cws_instrumentation_arm64	neutral	2.729 MiB → 3.090
✅	docker_dogstatsd_amd64	neutral	15.174 MiB → 15.820
✅	docker_dogstatsd_arm64	neutral	14.490 MiB → 14.830
✅	dogstatsd_deb_amd64	+2.75 KiB (0.03% increase)	7.894 → 7.897 → 8.790
✅	dogstatsd_deb_arm64	neutral	6.777 MiB → 7.710
✅	dogstatsd_rpm_amd64	neutral	7.905 MiB → 8.800
✅	dogstatsd_suse_amd64	neutral	7.905 MiB → 8.800
✅	iot_agent_deb_amd64	+3.28 KiB (0.03% increase)	11.404 → 11.407 → 12.040
✅	iot_agent_deb_arm64	-3.57 KiB (0.04% reduction)	9.707 → 9.704 → 10.450
✅	iot_agent_deb_armhf	neutral	9.943 MiB → 10.620

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 6a2f37e0-6a16-4b9e-aef1-46b9a0c54bd8

Baseline: 6956aee
Comparison: 95d4ab7
Diff

Optimization Goals: ✅ No significant changes detected

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	-0.52	[-3.55, +2.50]	1	Logs

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	quality_gate_logs	% cpu utilization	+1.88	[+0.27, +3.48]	1	Logs bounds checks dashboard
➖	quality_gate_metrics_logs	memory utilization	+1.20	[+0.95, +1.44]	1	Logs bounds checks dashboard
➖	ddot_metrics_sum_cumulativetodelta_exporter	memory utilization	+0.39	[+0.17, +0.62]	1	Logs
➖	docker_containers_memory	memory utilization	+0.08	[-0.01, +0.16]	1	Logs
➖	uds_dogstatsd_20mb_12k_contexts_20_senders	memory utilization	+0.05	[-0.01, +0.12]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	+0.03	[-0.37, +0.43]	1	Logs
➖	quality_gate_idle	memory utilization	+0.01	[-0.04, +0.06]	1	Logs bounds checks dashboard
➖	uds_dogstatsd_to_api_v3	ingress throughput	+0.00	[-0.20, +0.20]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	-0.00	[-0.43, +0.43]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.01	[-0.11, +0.10]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	-0.01	[-0.21, +0.19]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	-0.02	[-0.13, +0.10]	1	Logs
➖	ddot_metrics_sum_delta	memory utilization	-0.05	[-0.23, +0.13]	1	Logs
➖	quality_gate_idle_all_features	memory utilization	-0.05	[-0.09, -0.02]	1	Logs bounds checks dashboard
➖	file_to_blackhole_0ms_latency	egress throughput	-0.05	[-0.57, +0.46]	1	Logs
➖	ddot_metrics	memory utilization	-0.13	[-0.31, +0.06]	1	Logs
➖	otlp_ingest_logs	memory utilization	-0.14	[-0.24, -0.04]	1	Logs
➖	otlp_ingest_metrics	memory utilization	-0.22	[-0.38, -0.06]	1	Logs
➖	file_tree	memory utilization	-0.30	[-0.36, -0.24]	1	Logs
➖	ddot_metrics_sum_cumulative	memory utilization	-0.37	[-0.51, -0.22]	1	Logs
➖	ddot_logs	memory utilization	-0.49	[-0.56, -0.43]	1	Logs
➖	docker_containers_cpu	% cpu utilization	-0.52	[-3.55, +2.50]	1	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-1.09	[-1.28, -0.90]	1	Logs

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	docker_containers_cpu	simple_check_run	10/10	682 ≥ 26
✅	docker_containers_memory	memory_usage	10/10	272.98MiB ≤ 370MiB
✅	docker_containers_memory	simple_check_run	10/10	681 ≥ 26
✅	file_to_blackhole_0ms_latency	memory_usage	10/10	0.19GiB ≤ 1.20GiB
✅	file_to_blackhole_0ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10	0.23GiB ≤ 1.20GiB
✅	file_to_blackhole_1000ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_100ms_latency	memory_usage	10/10	0.20GiB ≤ 1.20GiB
✅	file_to_blackhole_100ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_500ms_latency	memory_usage	10/10	0.21GiB ≤ 1.20GiB
✅	file_to_blackhole_500ms_latency	missed_bytes	10/10	0B = 0B
✅	quality_gate_idle	intake_connections	10/10	3 = 3	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	173.48MiB ≤ 181MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	3 = 3	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	485.66MiB ≤ 550MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	203.90MiB ≤ 220MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	355.47 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	3 ≤ 6	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	428.27MiB ≤ 475MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

• quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.

[alpatriciodd]

@codex

[TCheruy]

this is great!!!!!