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Merged
aojea merged 1 commit into from
Sep 19, 2026
+63 −2
Merged

bench: skip non-finite metric samples when parsing exposition output #441

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38 changes: 38 additions & 0 deletions cmd/sam-bench/report_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,12 @@
package main

import (
"context"
"encoding/json"
"net/http"
"net/http/httptest"
"os"
"path/filepath"
"strings"
"testing"
Comment on lines +18 to 25

@gemini-code-assist gemini-code-assist Bot Sep 19, 2026

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medium

3. Test coverage must follow the pyramid

Import time to allow setting a timeout on the context used in the integration test, adhering to Rule 3.5 of the Repository Style Guide.

Suggested change
"context"
"encoding/json"
"net/http"
"net/http/httptest"
"os"
"path/filepath"
"strings"
"testing"
"context"
"encoding/json"
"net/http"
"net/http/httptest"
"os"
"path/filepath"
"strings"
"testing"
"time"
References
  1. Rule 3.5: Integration tests must be time bounded. Look for unbounded waits, time.Sleep longer than a few hundred milliseconds, or polling without a deadline. Prefer context.WithTimeout and t.Deadline(). (link)


Expand Down Expand Up @@ -104,6 +110,38 @@ func TestGaugeIgnoresSourcesThatNeverReportedIt(t *testing.T) {
}
}

func TestWriteObservationWithNonFiniteMetrics(t *testing.T) {
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
_, _ = w.Write([]byte("unavailable NaN\npositive +Inf\nnegative -Inf\nfinite 3\n"))
}))
defer server.Close()

metrics, err := scrapeAll(context.Background(), []string{server.URL})
if err != nil {
t.Fatalf("scrapeAll: %v", err)
}
Comment on lines +119 to +122

@gemini-code-assist gemini-code-assist Bot Sep 19, 2026

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medium

3. Test coverage must follow the pyramid

According to Rule 3.5 of the Repository Style Guide, integration tests must be time-bounded to avoid unbounded waits. Since scrapeAll performs HTTP requests, use a context with a timeout instead of context.Background().

Suggested change
metrics, err := scrapeAll(context.Background(), []string{server.URL})
if err != nil {
t.Fatalf("scrapeAll: %v", err)
}
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
metrics, err := scrapeAll(ctx, []string{server.URL})
if err != nil {
t.Fatalf("scrapeAll: %v", err)
}
References
  1. Rule 3.5: Integration tests must be time bounded. Look for unbounded waits, time.Sleep longer than a few hundred milliseconds, or polling without a deadline. Prefer context.WithTimeout and t.Deadline(). (link)

path := filepath.Join(t.TempDir(), "observation.json")
wantReport := &bench.Report{Requests: 1, Succeeded: 1}
if err := write(path, observation{Report: wantReport, After: metrics}); err != nil {
t.Fatalf("write: %v", err)
}

data, err := os.ReadFile(path)
if err != nil {
t.Fatalf("ReadFile: %v", err)
}
var got observation
if err := json.Unmarshal(data, &got); err != nil {
t.Fatalf("json.Unmarshal: %v", err)
}
if got.Report == nil || got.Report.Requests != 1 || got.Report.Succeeded != 1 {
t.Errorf("report = %+v, want %+v", got.Report, wantReport)
}
if values := got.After[server.URL]; len(values) != 1 || values["finite"] != 3 {
t.Errorf("metrics = %v, want only finite=3", values)
}
}

func TestRenderPutsEveryObservationInTheTable(t *testing.T) {
observations := []observation{
{
Expand Down
5 changes: 3 additions & 2 deletions internal/bench/scrape.go
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ import (
"bufio"
"context"
"fmt"
"math"
"net/http"
"sort"
"strconv"
Expand Down Expand Up @@ -170,8 +171,8 @@ func parseExposition(r interface{ Read([]byte) (int, error) }) ([]Series, error)
continue
}
value, err := strconv.ParseFloat(fields[0], 64)
if err != nil {
// NaN and +Inf are legal values that carry no information here.
if err != nil || math.IsNaN(value) || math.IsInf(value, 0) {
// NaN and infinity are legal values that carry no information here.
continue
}

Expand Down
22 changes: 22 additions & 0 deletions internal/bench/scrape_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ package bench

import (
"context"
"encoding/json"
"net/http"
"net/http/httptest"
"strings"
Expand Down Expand Up @@ -85,6 +86,27 @@ func TestParseExpositionKeepsCommasInsideLabelValues(t *testing.T) {
}
}

func TestParseExpositionNonFinite(t *testing.T) {
series, err := parseExposition(strings.NewReader("unavailable NaN\npositive +Inf\nnegative -Inf\nfinite 3\nzero 0\nfinite_negative -2.5\n"))
if err != nil {
t.Fatalf("parseExposition: %v", err)
}

metrics := (&Snapshot{Series: series}).Flatten()
want := map[string]float64{"finite": 3, "zero": 0, "finite_negative": -2.5}
if len(metrics) != len(want) {
t.Fatalf("metrics = %v, want %v", metrics, want)
}
for name, value := range want {
if got, ok := metrics[name]; !ok || got != value {
t.Errorf("metric %q = %v (found %v), want %v", name, got, ok, value)
}
}
if _, err := json.Marshal(metrics); err != nil {
t.Fatalf("json.Marshal: %v", err)
}
}

func TestScrapeReadsALiveEndpoint(t *testing.T) {
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
_, _ = w.Write([]byte("sam_node_requests_in_flight 3\n"))
Expand Down
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