Remove the use of InjectRule in UrlFetchUtilsTest

Random used to be a static variable which requires InjectRule to mock it in unit tests. It is now a singleton, which ensures that the same instance is called every time and Random.nextBytes() generates results that distribute uniformly between each call.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=217592767

java/google/registry/config/RegistryConfig.java

@@ -14,6 +14,7 @@
 
 package google.registry.config;
 
+import static com.google.common.base.Randoms.insecureRandom;
 import static com.google.common.base.Suppliers.memoize;
 import static google.registry.config.ConfigUtils.makeUrl;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
@@ -34,6 +35,7 @@ import java.lang.annotation.Retention;
 import java.net.URI;
 import java.net.URL;
 import java.util.Optional;
+import java.util.Random;
 import java.util.stream.Collectors;
 import javax.annotation.Nullable;
 import javax.inject.Named;
@@ -1257,6 +1259,17 @@ public final class RegistryConfig {
               .build())
           .build();
     }
+
+    /**
+     * Returns a singleton random number generator.
+     *
+     * @see google.registry.util.UrlFetchUtils
+     */
+    @Singleton
+    @Provides
+    public static Random provideRandom() {
+      return insecureRandom();
+    }
   }
 
   /**

java/google/registry/tmch/NordnUploadAction.java

@@ -80,6 +80,7 @@ public final class NordnUploadAction implements Runnable {
   private final String actionLogId = String.valueOf(1000000000 + new Random().nextInt(1000000000));
 
   @Inject Clock clock;
+  @Inject Random random;
   @Inject LordnRequestInitializer lordnRequestInitializer;
   @Inject URLFetchService fetchService;
   @Inject @Config("tmchMarksdbUrl") String tmchMarksdbUrl;
@@ -138,7 +139,7 @@ public final class NordnUploadAction implements Runnable {
         "LORDN upload task %s: Sending to URL: %s ; data: %s", actionLogId, url, csvData);
     HTTPRequest req = new HTTPRequest(new URL(url), POST, validateCertificate().setDeadline(60d));
     lordnRequestInitializer.initialize(req, tld);
-    setPayloadMultipart(req, "file", "claims.csv", CSV_UTF_8, csvData);
+    setPayloadMultipart(req, "file", "claims.csv", CSV_UTF_8, csvData, random);
     HTTPResponse rsp = fetchService.fetch(req);
     logger.atInfo().log(
         "LORDN upload task %s response: HTTP response code %d, response data: %s",

java/google/registry/util/UrlFetchUtils.java

@@ -35,9 +35,6 @@ import java.util.Random;
 /** Helper methods for the App Engine URL fetch service. */
 public final class UrlFetchUtils {
 
-  @NonFinalForTesting
-  private static Random random = new Random();
-
   /** Returns value of first header matching {@code name}. */
   public static Optional<String> getHeaderFirst(HTTPResponse rsp, String name) {
     return getHeaderFirstInternal(rsp.getHeadersUncombined(), name);
@@ -63,11 +60,16 @@ public final class UrlFetchUtils {
    *
    * <p>This is equivalent to running the command: {@code curl -F fieldName=@payload.txt URL}
    *
-   * @see <a href="http://www.ietf.org/rfc/rfc2388.txt"> RFC2388 - Returning Values from Forms</a>
+   * @see <a href="http://www.ietf.org/rfc/rfc2388.txt">RFC2388 - Returning Values from Forms</a>
    */
   public static void setPayloadMultipart(
-      HTTPRequest request, String name, String filename, MediaType contentType, String data) {
-    String boundary = createMultipartBoundary();
+      HTTPRequest request,
+      String name,
+      String filename,
+      MediaType contentType,
+      String data,
+      Random random) {
+    String boundary = createMultipartBoundary(random);
     checkState(
         !data.contains(boundary),
         "Multipart data contains autogenerated boundary: %s", boundary);
@@ -87,7 +89,7 @@ public final class UrlFetchUtils {
     request.setPayload(payload);
   }
 
-  private static String createMultipartBoundary() {
+  private static String createMultipartBoundary(Random random) {
     // Generate 192 random bits (24 bytes) to produce 192/log_2(64) = 192/6 = 32 base64 digits.
     byte[] rand = new byte[24];
     random.nextBytes(rand);