final

test/loadtest_test.go

@@ -0,0 +1,126 @@
+package main
+
+import (
+	"net/url"
+	"reflect"
+	"testing"
+)
+
+func TestParsePageMixDistributesRangeWeights(t *testing.T) {
+	buckets, err := parsePageMix("1-3:60,4-10:30,11-20:10")
+	if err != nil {
+		t.Fatalf("parsePageMix returned an error: %v", err)
+	}
+
+	if len(buckets) != 20 {
+		t.Fatalf("expected 20 page buckets, got %d", len(buckets))
+	}
+
+	for page := 1; page <= 20; page++ {
+		bucket := buckets[page-1]
+		if bucket.page != page {
+			t.Errorf("bucket %d has page %d", page-1, bucket.page)
+		}
+
+		expectedWeight := 1.0
+		if page <= 3 {
+			expectedWeight = 20
+		} else if page <= 10 {
+			expectedWeight = 30.0 / 7
+		}
+		if bucket.weight != expectedWeight {
+			t.Errorf("page %d has weight %v, want %v", page, bucket.weight, expectedWeight)
+		}
+	}
+}
+
+func TestParsePageMixRejectsInvalidSpecifications(t *testing.T) {
+	invalidSpecs := []string{
+		"1-3",
+		"0:1",
+		"3-1:1",
+		"1-3:0",
+		"letters:1",
+		"1:1,1:2",
+	}
+
+	for _, spec := range invalidSpecs {
+		t.Run(spec, func(t *testing.T) {
+			if _, err := parsePageMix(spec); err == nil {
+				t.Fatalf("parsePageMix(%q) returned nil error", spec)
+			}
+		})
+	}
+}
+
+func TestSelectPagesUsesConfiguredWeights(t *testing.T) {
+	buckets, err := parsePageMix("1-3:60,4-10:30,11-20:10")
+	if err != nil {
+		t.Fatalf("parsePageMix returned an error: %v", err)
+	}
+
+	pages := selectPages(buckets, 10000, 42)
+	if len(pages) != 10000 {
+		t.Fatalf("expected 10000 selected pages, got %d", len(pages))
+	}
+
+	counts := make(map[int]int)
+	for _, page := range pages {
+		counts[page]++
+	}
+
+	assertCountNear(t, "pages 1-3", counts[1]+counts[2]+counts[3], 6000, 150)
+	assertCountNear(t, "pages 4-10", sumPageCounts(counts, 4, 10), 3000, 150)
+	assertCountNear(t, "pages 11-20", sumPageCounts(counts, 11, 20), 1000, 100)
+}
+
+func TestSelectPagesIsReproducibleWithSeed(t *testing.T) {
+	buckets, err := parsePageMix("1:3,2:1")
+	if err != nil {
+		t.Fatalf("parsePageMix returned an error: %v", err)
+	}
+
+	first := selectPages(buckets, 20, 42)
+	second := selectPages(buckets, 20, 42)
+	if !reflect.DeepEqual(first, second) {
+		t.Fatalf("page selections differ for the same seed: %v != %v", first, second)
+	}
+}
+
+func TestURLForPageReplacesOnlyPageParameter(t *testing.T) {
+	base, err := url.Parse("https://example.test/api/playertotals?page=1&pageSize=50&season=2025")
+	if err != nil {
+		t.Fatalf("url.Parse returned an error: %v", err)
+	}
+
+	requestURL, err := url.Parse(urlForPage(*base, 7))
+	if err != nil {
+		t.Fatalf("url.Parse returned an error: %v", err)
+	}
+
+	query := requestURL.Query()
+	if query.Get("page") != "7" {
+		t.Errorf("page query parameter = %q, want 7", query.Get("page"))
+	}
+	if query.Get("pageSize") != "50" {
+		t.Errorf("pageSize query parameter = %q, want 50", query.Get("pageSize"))
+	}
+	if query.Get("season") != "2025" {
+		t.Errorf("season query parameter = %q, want 2025", query.Get("season"))
+	}
+}
+
+func assertCountNear(t *testing.T, label string, actual, expected, tolerance int) {
+	t.Helper()
+	if actual < expected-tolerance || actual > expected+tolerance {
+		t.Errorf("%s count = %d, want %d +/- %d", label, actual, expected, tolerance)
+	}
+}
+
+func sumPageCounts(counts map[int]int, firstPage, lastPage int) int {
+	total := 0
+	for page := firstPage; page <= lastPage; page++ {
+		total += counts[page]
+	}
+	return total
+}