feat: make generated test values comply with url path template (#903)

This includes nested messages creation when there are url paths with subfields mentioned (like `/v1/{field.name=projects/*/databases/*/collectionGroups/*/fields/*}`)

This is needed for rest transports tests because, unlike grpc, request fields must match path templates for rest logic pass the tests.

Main changes are in `DefaultValueComposer` and `HttpRuleParser` classes.

The generated pattern-matching samples are in the following format:
  given the pattern pattern:
  `/v1/{field.name=projects/*/databases/*/collectionGroups/*/fields/*}`
  the value will be:
  `field.name=projects/project-1234/databases/database-1234/collectionGroups/collectionGroup-1234/fields/field-1234`

gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceClientTestClassComposer.java

@@ -354,7 +354,7 @@ private MethodDefinition createRpcTestMethod(
           AssignmentExpr.builder()
               .setVariableExpr(responsesElementVarExpr.toBuilder().setIsDecl(true).build())
               .setValueExpr(
-                  DefaultValueComposer.createDefaultValue(
+                  DefaultValueComposer.createValue(
                       Field.builder()
                           .setType(repeatedResponseType)
                           .setName("responsesElement")
@@ -377,23 +377,23 @@ private MethodDefinition createRpcTestMethod(
               method.name(), methodOutputMessage.name()));
 
       expectedResponseValExpr =
-          DefaultValueComposer.createSimplePagedResponse(
+          DefaultValueComposer.createSimplePagedResponseValue(
               method.outputType(),
               firstRepeatedField.name(),
               responsesElementVarExpr,
               firstRepeatedField.isMap());
     } else {
       if (messageTypes.containsKey(methodOutputType.reference().fullName())) {
         expectedResponseValExpr =
-            DefaultValueComposer.createSimpleMessageBuilderExpr(
+            DefaultValueComposer.createSimpleMessageBuilderValue(
                 messageTypes.get(methodOutputType.reference().fullName()),
                 resourceNames,
                 messageTypes);
       } else {
         // Wrap this in a field so we don't have to split the helper into lots of different methods,
         // or duplicate it for VariableExpr.
         expectedResponseValExpr =
-            DefaultValueComposer.createDefaultValue(
+            DefaultValueComposer.createValue(
                 Field.builder()
                     .setType(methodOutputType)
                     .setIsMessage(true)
@@ -422,7 +422,7 @@ private MethodDefinition createRpcTestMethod(
           AssignmentExpr.builder()
               .setVariableExpr(resultOperationVarExpr.toBuilder().setIsDecl(true).build())
               .setValueExpr(
-                  DefaultValueComposer.createSimpleOperationBuilderExpr(
+                  DefaultValueComposer.createSimpleOperationBuilderValue(
                       String.format("%sTest", JavaStyle.toLowerCamelCase(method.name())),
                       expectedResponseVarExpr))
               .build());
@@ -457,22 +457,32 @@ private MethodDefinition createRpcTestMethod(
       argExprs.add(requestVarExpr);
       requestMessage = messageTypes.get(method.inputType().reference().fullName());
       Preconditions.checkNotNull(requestMessage);
+      Map<String, String> pathParamValuePatterns = Collections.emptyMap();
+      if (getTransportContext().useValuePatterns() && method.hasHttpBindings()) {
+        pathParamValuePatterns = method.httpBindings().getPathParametersValuePatterns();
+      }
       Expr valExpr =
-          DefaultValueComposer.createSimpleMessageBuilderExpr(
-              requestMessage, resourceNames, messageTypes);
+          DefaultValueComposer.createSimpleMessageBuilderValue(
+              requestMessage, resourceNames, messageTypes, pathParamValuePatterns);
       methodExprs.add(
           AssignmentExpr.builder()
               .setVariableExpr(requestVarExpr.toBuilder().setIsDecl(true).build())
               .setValueExpr(valExpr)
               .build());
     } else {
+      Map<String, String> valuePatterns = Collections.emptyMap();
+      if (getTransportContext().useValuePatterns() && method.hasHttpBindings()) {
+        valuePatterns = method.httpBindings().getPathParametersValuePatterns();
+      }
       for (MethodArgument methodArg : methodSignature) {
         String methodArgName = JavaStyle.toLowerCamelCase(methodArg.name());
         VariableExpr varExpr =
             VariableExpr.withVariable(
                 Variable.builder().setType(methodArg.type()).setName(methodArgName).build());
         argExprs.add(varExpr);
-        Expr valExpr = createDefaultValue(methodArg, resourceNames);
+        Expr valExpr =
+            DefaultValueComposer.createMethodArgValue(
+                methodArg, resourceNames, messageTypes, valuePatterns);
         methodExprs.add(
             AssignmentExpr.builder()
                 .setVariableExpr(varExpr.toBuilder().setIsDecl(true).build())
@@ -737,9 +747,6 @@ protected abstract List<Statement> createStreamingRpcExceptionTestStatements(
       Map<String, ResourceName> resourceNames,
       Map<String, Message> messageTypes);
 
-  protected abstract Expr createDefaultValue(
-      MethodArgument methodArg, Map<String, ResourceName> resourceNames);
-
   protected List<Statement> createRpcExceptionTestStatements(
       Method method,
       List<MethodArgument> methodSignature,
@@ -748,6 +755,7 @@ protected List<Statement> createRpcExceptionTestStatements(
       Map<String, Message> messageTypes) {
     List<VariableExpr> argVarExprs = new ArrayList<>();
     List<Expr> tryBodyExprs = new ArrayList<>();
+
     if (methodSignature.isEmpty()) {
       // Construct the actual request.
       VariableExpr varExpr =
@@ -756,22 +764,32 @@ protected List<Statement> createRpcExceptionTestStatements(
       argVarExprs.add(varExpr);
       Message requestMessage = messageTypes.get(method.inputType().reference().fullName());
       Preconditions.checkNotNull(requestMessage);
+      Map<String, String> valuePatterns = Collections.emptyMap();
+      if (getTransportContext().useValuePatterns() && method.hasHttpBindings()) {
+        valuePatterns = method.httpBindings().getPathParametersValuePatterns();
+      }
       Expr valExpr =
-          DefaultValueComposer.createSimpleMessageBuilderExpr(
-              requestMessage, resourceNames, messageTypes);
+          DefaultValueComposer.createSimpleMessageBuilderValue(
+              requestMessage, resourceNames, messageTypes, valuePatterns);
       tryBodyExprs.add(
           AssignmentExpr.builder()
               .setVariableExpr(varExpr.toBuilder().setIsDecl(true).build())
               .setValueExpr(valExpr)
               .build());
     } else {
+      Map<String, String> valuePatterns = Collections.emptyMap();
+      if (getTransportContext().useValuePatterns() && method.hasHttpBindings()) {
+        valuePatterns = method.httpBindings().getPathParametersValuePatterns();
+      }
       for (MethodArgument methodArg : methodSignature) {
         String methodArgName = JavaStyle.toLowerCamelCase(methodArg.name());
         VariableExpr varExpr =
             VariableExpr.withVariable(
                 Variable.builder().setType(methodArg.type()).setName(methodArgName).build());
         argVarExprs.add(varExpr);
-        Expr valExpr = createDefaultValue(methodArg, resourceNames);
+        Expr valExpr =
+            DefaultValueComposer.createMethodArgValue(
+                methodArg, resourceNames, messageTypes, valuePatterns);
         tryBodyExprs.add(
             AssignmentExpr.builder()
                 .setVariableExpr(varExpr.toBuilder().setIsDecl(true).build())

gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/TransportContext.java

@@ -81,6 +81,8 @@ public abstract class TransportContext {
 
   public abstract List<String> operationsClientNames();
 
+  public abstract boolean useValuePatterns();
+
   protected static TypeNode classToType(Class<?> clazz) {
     return TypeNode.withReference(ConcreteReference.withClazz(clazz));
   }
@@ -140,6 +142,8 @@ public abstract Builder setTransportApiClientHeaderProviderBuilderNames(
 
     public abstract Builder setOperationsClientNames(List<String> operationsClientNames);
 
+    public abstract Builder setUseValuePatterns(boolean useValuePatterns);
+
     public abstract TransportContext build();
   }
 }