[ggj][codegen][test] fix: ensure all testgen methods throw Exceptions

src/main/java/com/google/api/generator/engine/ast/AnonymousClassExpr.java

@@ -17,6 +17,7 @@
 import com.google.auto.value.AutoValue;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
@@ -45,6 +46,10 @@ public static Builder builder() {
   public abstract static class Builder {
     public abstract Builder setType(TypeNode type);
 
+    public Builder setMethods(MethodDefinition... methods) {
+      return setMethods(Arrays.asList(methods));
+    }
+
     public abstract Builder setMethods(List<MethodDefinition> methods);
 
     public abstract Builder setStatements(List<Statement> statements);

src/main/java/com/google/api/generator/engine/ast/ConcreteReference.java

@@ -16,6 +16,7 @@
 
 import com.google.auto.value.AutoValue;
 import com.google.common.collect.ImmutableList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
 import javax.annotation.Nullable;
@@ -210,7 +211,11 @@ public abstract static class Builder {
 
     public abstract Builder setWildcardUpperBound(Reference reference);
 
-    public abstract Builder setGenerics(List<Reference> clazzes);
+    public Builder setGenerics(Reference... references) {
+      return setGenerics(Arrays.asList(references));
+    }
+
+    public abstract Builder setGenerics(List<Reference> references);
 
     public abstract Builder setIsStaticImport(boolean isStaticImport);
 

src/main/java/com/google/api/generator/engine/ast/TypeNode.java

@@ -186,6 +186,10 @@ public boolean isPrimitiveType() {
     return isPrimitiveType(typeKind());
   }
 
+  public boolean isProtoPrimitiveType() {
+    return isPrimitiveType() || this.equals(TypeNode.STRING);
+  }
+
   public boolean isSupertypeOrEquals(TypeNode other) {
     boolean oneTypeIsNull = this.equals(TypeNode.NULL) ^ other.equals(TypeNode.NULL);
     return !isPrimitiveType()

src/main/java/com/google/api/generator/engine/ast/VaporReference.java

@@ -17,6 +17,7 @@
 import com.google.auto.value.AutoValue;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
 import javax.annotation.Nullable;
@@ -146,6 +147,10 @@ public abstract static class Builder {
 
     public abstract Builder setUseFullName(boolean useFullName);
 
+    public Builder setGenerics(Reference... references) {
+      return setGenerics(Arrays.asList(references));
+    }
+
     public abstract Builder setGenerics(List<Reference> clazzes);
 
     public abstract Builder setEnclosingClassName(String enclosingClassName);

src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java

@@ -22,6 +22,7 @@
 import com.google.api.generator.engine.ast.StringObjectValue;
 import com.google.api.generator.engine.ast.TypeNode;
 import com.google.api.generator.engine.ast.ValueExpr;
+import com.google.api.generator.engine.ast.Variable;
 import com.google.api.generator.engine.ast.VariableExpr;
 import com.google.api.generator.gapic.model.Field;
 import com.google.api.generator.gapic.model.Message;
@@ -32,6 +33,7 @@
 import com.google.common.base.Preconditions;
 import com.google.longrunning.Operation;
 import com.google.protobuf.Any;
+import com.google.protobuf.ByteString;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -44,6 +46,8 @@ public class DefaultValueComposer {
   private static TypeNode OPERATION_TYPE =
       TypeNode.withReference(ConcreteReference.withClazz(Operation.class));
   private static TypeNode ANY_TYPE = TypeNode.withReference(ConcreteReference.withClazz(Any.class));
+  private static TypeNode BYTESTRING_TYPE =
+      TypeNode.withReference(ConcreteReference.withClazz(ByteString.class));
 
   static Expr createDefaultValue(
       MethodArgument methodArg, Map<String, ResourceName> resourceNames) {
@@ -122,6 +126,13 @@ static Expr createDefaultValue(Field f) {
           PrimitiveValue.builder().setType(f.type()).setValue("true").build());
     }
 
+    if (f.type().equals(BYTESTRING_TYPE)) {
+      return VariableExpr.builder()
+          .setStaticReferenceType(BYTESTRING_TYPE)
+          .setVariable(Variable.builder().setName("EMPTY").setType(BYTESTRING_TYPE).build())
+          .build();
+    }
+
     throw new UnsupportedOperationException(
         String.format(
             "Default value for field %s with type %s not implemented yet.", f.name(), f.type()));
@@ -283,7 +294,8 @@ static Expr createSimpleOperationBuilderExpr(String name, VariableExpr responseE
         .build();
   }
 
-  static Expr createSimplePagedResponse(TypeNode responseType, Expr responseElementVarExpr) {
+  static Expr createSimplePagedResponse(
+      TypeNode responseType, String repeatedFieldName, Expr responseElementVarExpr) {
     Expr pagedResponseExpr =
         MethodInvocationExpr.builder()
             .setStaticReferenceType(responseType)
@@ -298,7 +310,7 @@ static Expr createSimplePagedResponse(TypeNode responseType, Expr responseElemen
     pagedResponseExpr =
         MethodInvocationExpr.builder()
             .setExprReferenceExpr(pagedResponseExpr)
-            .setMethodName("addAllResponses")
+            .setMethodName(String.format("addAll%s", JavaStyle.toUpperCamelCase(repeatedFieldName)))
             .setArguments(
                 MethodInvocationExpr.builder()
                     .setStaticReferenceType(