Core Rule Set tests: load each set of settings once (closes #252)

Tests now share one Core Rule Set for each set of settings, loaded once
through sync.OnceValues in shared(). Exclusions-file tests and
TestCorazaWritesNoFile still load their own: loading is what they check.

Loading was not most of the time: the WordPress and Drupal recorded
requests, inspected one after another, were. Each recorded request now
runs as its own parallel subtest, with the same request and outcome.

Model: opus-5-5

internal/coreruleset/coreruleset_test.go

@@ -2,6 +2,7 @@ package coreruleset_test
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"net/netip"
@@ -12,6 +13,7 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+	"sync"
 	"testing"
 
 	"sneak.berlin/go/smallwebwaf/internal/coreruleset"
@@ -23,14 +25,37 @@ import (
 //nolint:gochecknoglobals // a constant cannot be a list
 var defaultDisabledRules = []int{920340, 920420, 920440, 920640, 930130, 930140}
 
-// newCoreRuleSet returns the Core Rule Set at paranoia level level, with
+// loaded holds a loader of the Core Rule Set for each set of settings
-// the rules in disabled switched off.
+// the tests have asked for, by the settings, so that each is loaded once.
-func newCoreRuleSet(t *testing.T, level int, disabled ...int) *coreruleset.CoreRuleSet {
+//
+//nolint:gochecknoglobals // the tests share it
+var loaded = struct {
+	sync.Mutex
+
+	loaders map[string]func() (*coreruleset.CoreRuleSet, error)
+}{loaders: map[string]func() (*coreruleset.CoreRuleSet, error){}}
+
+// shared returns the Core Rule Set with params, loaded once for every
+// test that asks for the same settings. Loading takes most of the time
+// the tests take.
+func shared(t *testing.T, params coreruleset.Params) *coreruleset.CoreRuleSet {
 	t.Helper()
 
-	crs, err := coreruleset.New(coreruleset.Params{
+	settings := fmt.Sprintf("%+v", params)
-		ParanoiaLevel: level, DisabledRules: disabled,
+
+	loaded.Lock()
+
+	load, found := loaded.loaders[settings]
+	if !found {
+		load = sync.OnceValues(func() (*coreruleset.CoreRuleSet, error) {
+			return coreruleset.New(params)
 		})
+		loaded.loaders[settings] = load
+	}
+
+	loaded.Unlock()
+
+	crs, err := load()
 	if err != nil {
 		t.Fatalf("load the Core Rule Set: %v", err)
 	}
@@ -38,6 +63,14 @@ func newCoreRuleSet(t *testing.T, level int, disabled ...int) *coreruleset.CoreR
 	return crs
 }
 
+// newCoreRuleSet returns the Core Rule Set at paranoia level level, with
+// the rules in disabled switched off.
+func newCoreRuleSet(t *testing.T, level int, disabled ...int) *coreruleset.CoreRuleSet {
+	t.Helper()
+
+	return shared(t, coreruleset.Params{ParanoiaLevel: level, DisabledRules: disabled})
+}
+
 // request is a request a test inspects: its method, its target, the path
 // and the query as a client sends them, and its headers, each written
 // "Name: value".
@@ -612,14 +645,9 @@ func recordedRequests(t *testing.T, name string) []recordedRequest {
 func readingBodiesUpTo64K(t *testing.T) *coreruleset.CoreRuleSet {
 	t.Helper()
 
-	crs, err := coreruleset.New(coreruleset.Params{
+	return shared(t, coreruleset.Params{
 		ParanoiaLevel: 1, DisabledRules: defaultDisabledRules, BodyLimit: 64<<10 - 1,
 	})
-	if err != nil {
-		t.Fatalf("load the Core Rule Set: %v", err)
-	}
-
-	return crs
 }
 
 // wordpressAttackTargets returns attack in a query parameter no exclusion
@@ -676,6 +704,9 @@ func TestOrdinaryWordPressRequestsPassAndAttacksAreRefused(t *testing.T) {
 	defaults, bodies := atDefaults(t), readingBodiesUpTo64K(t)
 
 	for _, recorded := range recordedRequests(t, "wordpress-requests.txt") {
+		t.Run(recorded.Method+" "+recorded.Target, func(t *testing.T) {
+			t.Parallel()
+
 			r := request{recorded.Method, recorded.Target, recorded.Headers}
 
 			crsSets := []*coreruleset.CoreRuleSet{defaults}
@@ -689,6 +720,7 @@ func TestOrdinaryWordPressRequestsPassAndAttacksAreRefused(t *testing.T) {
 					t.Errorf("%s %s %.200q refused: %+v", r.method, r.target, recorded.Body, got)
 				}
 			}
+		})
 	}
 
 	for _, attack := range []string{
@@ -1064,14 +1096,9 @@ const injection = "1' OR '1'='1"
 func readingBodies(t *testing.T) *coreruleset.CoreRuleSet {
 	t.Helper()
 
-	crs, err := coreruleset.New(coreruleset.Params{
+	return shared(t, coreruleset.Params{
 		ParanoiaLevel: 1, DisabledRules: defaultDisabledRules, BodyLimit: bodyLimit,
 	})
-	if err != nil {
-		t.Fatalf("load the Core Rule Set: %v", err)
-	}
-
-	return crs
 }
 
 // post is a POST request for / with a body of the type contentType, a
@@ -1356,10 +1383,19 @@ func TestCorazaWritesNoFile(t *testing.T) {
 	// refuses to load, and could not write a file of a multipart body.
 	t.Setenv("TMPDIR", filepath.Join(t.TempDir(), "missing"))
 
+	// The test loads its own Core Rule Set, since loading is part of what
+	// it checks.
+	crs, err := coreruleset.New(coreruleset.Params{
+		ParanoiaLevel: 1, DisabledRules: defaultDisabledRules, BodyLimit: bodyLimit,
+	})
+	if err != nil {
+		t.Fatalf("load the Core Rule Set: %v", err)
+	}
+
 	body := "--b\r\nContent-Disposition: form-data; name=\"file\"; " +
 		"filename=\"notes.txt\"\r\nContent-Type: text/plain\r\n\r\n" +
 		strings.Repeat("a", 1000) + "\r\n" + field("q", injection) + end
-	wantBody(t, readingBodies(t), post(multipart), body, matched(942100), body)
+	wantBody(t, crs, post(multipart), body, matched(942100), body)
 }
 
 func TestBodyLimitOf1GLoads(t *testing.T) {

internal/coreruleset/drupal_test.go

@@ -21,6 +21,9 @@ func TestOrdinaryDrupalRequestsPass(t *testing.T) {
 	defaults, bodies := atDefaults(t), readingBodies(t)
 
 	for _, recorded := range recordedRequests(t, "drupal-requests.txt") {
+		t.Run(recorded.Method+" "+recorded.Target, func(t *testing.T) {
+			t.Parallel()
+
 			r := request{recorded.Method, recorded.Target, recorded.Headers}
 
 			got, _ := inspectBody(t, defaults, r, recorded.Body)
@@ -33,6 +36,7 @@ func TestOrdinaryDrupalRequestsPass(t *testing.T) {
 				t.Errorf("%s %s %.200q refused while bodies are read: %+v",
 					r.method, r.target, recorded.Body, got)
 			}
+		})
 	}
 }