diff --git a/BUILD b/BUILD
index 3e2a45b8a0adc19f03b37bf15e1ffdcdbf517476..ffeb31e424b852f5fdbd9a63039f08212306de96 100644
--- a/BUILD
+++ b/BUILD
@@ -223,6 +223,7 @@ cc_library(
     "src/core/surface/api_trace.h",
     "src/core/surface/byte_buffer_queue.h",
     "src/core/surface/call.h",
+    "src/core/surface/call_test_only.h",
     "src/core/surface/channel.h",
     "src/core/surface/completion_queue.h",
     "src/core/surface/event_string.h",
@@ -509,6 +510,7 @@ cc_library(
     "src/core/surface/api_trace.h",
     "src/core/surface/byte_buffer_queue.h",
     "src/core/surface/call.h",
+    "src/core/surface/call_test_only.h",
     "src/core/surface/channel.h",
     "src/core/surface/completion_queue.h",
     "src/core/surface/event_string.h",
@@ -1296,6 +1298,7 @@ objc_library(
     "src/core/surface/api_trace.h",
     "src/core/surface/byte_buffer_queue.h",
     "src/core/surface/call.h",
+    "src/core/surface/call_test_only.h",
     "src/core/surface/channel.h",
     "src/core/surface/completion_queue.h",
     "src/core/surface/event_string.h",
diff --git a/build.yaml b/build.yaml
index 98fb0348ca3bc32e78bda06193350b9fa9ff1795..e277b60b77e782c43c76e3710261e7b88a7b9dfa 100644
--- a/build.yaml
+++ b/build.yaml
@@ -183,6 +183,7 @@ filegroups:
   - src/core/surface/api_trace.h
   - src/core/surface/byte_buffer_queue.h
   - src/core/surface/call.h
+  - src/core/surface/call_test_only.h
   - src/core/surface/channel.h
   - src/core/surface/completion_queue.h
   - src/core/surface/event_string.h
diff --git a/gRPC.podspec b/gRPC.podspec
index 717e7005ee5d21208b301835a219ef70eb7cdc77..6378cf0413cde1dc51f3e5dea2fd800d58a576d7 100644
--- a/gRPC.podspec
+++ b/gRPC.podspec
@@ -227,6 +227,7 @@ Pod::Spec.new do |s|
                       'src/core/surface/api_trace.h',
                       'src/core/surface/byte_buffer_queue.h',
                       'src/core/surface/call.h',
+                      'src/core/surface/call_test_only.h',
                       'src/core/surface/channel.h',
                       'src/core/surface/completion_queue.h',
                       'src/core/surface/event_string.h',
@@ -518,6 +519,7 @@ Pod::Spec.new do |s|
                               'src/core/surface/api_trace.h',
                               'src/core/surface/byte_buffer_queue.h',
                               'src/core/surface/call.h',
+                              'src/core/surface/call_test_only.h',
                               'src/core/surface/channel.h',
                               'src/core/surface/completion_queue.h',
                               'src/core/surface/event_string.h',
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 8a7a772821ea314efee099d77c89fa5b21f9a8fb..022ca191cd741b797dcbbd71ce05308437a94e40 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -527,9 +527,13 @@ static void set_compression_algorithm(grpc_call *call,
   call->compression_algorithm = algo;
 }
 
-grpc_compression_algorithm grpc_call_get_compression_algorithm(
-    const grpc_call *call) {
-  return call->compression_algorithm;
+grpc_compression_algorithm grpc_call_test_only_get_compression_algorithm(
+    grpc_call *call) {
+  grpc_compression_algorithm algorithm;
+  gpr_mu_lock(&call->mu);
+  algorithm = call->compression_algorithm;
+  gpr_mu_unlock(&call->mu);
+  return algorithm;
 }
 
 static void set_encodings_accepted_by_peer(
@@ -563,12 +567,20 @@ static void set_encodings_accepted_by_peer(
   }
 }
 
-gpr_uint32 grpc_call_get_encodings_accepted_by_peer(grpc_call *call) {
-  return call->encodings_accepted_by_peer;
+gpr_uint32 grpc_call_test_only_get_encodings_accepted_by_peer(grpc_call *call) {
+  gpr_uint32 encodings_accepted_by_peer;
+  gpr_mu_lock(&call->mu);
+  encodings_accepted_by_peer = call->encodings_accepted_by_peer;
+  gpr_mu_unlock(&call->mu);
+  return encodings_accepted_by_peer;
 }
 
-gpr_uint32 grpc_call_get_message_flags(const grpc_call *call) {
-  return call->incoming_message_flags;
+gpr_uint32 grpc_call_test_only_get_message_flags(grpc_call *call) {
+  gpr_uint32 flags;
+  gpr_mu_lock(&call->mu);
+  flags = call->incoming_message_flags;
+  gpr_mu_unlock(&call->mu);
+  return flags;
 }
 
 static void set_status_details(grpc_call *call, status_source source,
diff --git a/src/core/surface/call.h b/src/core/surface/call.h
index f421a81619f7854c0f3024afea7721feadc5876c..9b7c6f9bfbed9e4bc174820fac8759bb5b449c9a 100644
--- a/src/core/surface/call.h
+++ b/src/core/surface/call.h
@@ -169,17 +169,6 @@ void *grpc_call_context_get(grpc_call *call, grpc_context_index elem);
 
 gpr_uint8 grpc_call_is_client(grpc_call *call);
 
-grpc_compression_algorithm grpc_call_get_compression_algorithm(
-    const grpc_call *call);
-
-gpr_uint32 grpc_call_get_message_flags(const grpc_call *call);
-
-/** Returns a bitset for the encodings (compression algorithms) supported by \a
- * call's peer.
- *
- * To be indexed by grpc_compression_algorithm enum values. */
-gpr_uint32 grpc_call_get_encodings_accepted_by_peer(grpc_call *call);
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/core/surface/call_test_only.h b/src/core/surface/call_test_only.h
new file mode 100644
index 0000000000000000000000000000000000000000..df4be3248b2a0baa58f16fdfcea7c10f131f01bb
--- /dev/null
+++ b/src/core/surface/call_test_only.h
@@ -0,0 +1,65 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_SURFACE_CALL_TEST_ONLY_H
+#define GRPC_INTERNAL_CORE_SURFACE_CALL_TEST_ONLY_H
+
+#include <grpc/grpc.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Return the compression algorithm from \a call.
+ *
+ * \warning This function should \b only be used in test code. */
+grpc_compression_algorithm grpc_call_test_only_get_compression_algorithm(
+    grpc_call *call);
+
+/** Return the message flags from \a call.
+ *
+ * \warning This function should \b only be used in test code. */
+gpr_uint32 grpc_call_test_only_get_message_flags(grpc_call *call);
+
+/** Returns a bitset for the encodings (compression algorithms) supported by \a
+ * call's peer.
+ *
+ * To be indexed by grpc_compression_algorithm enum values. */
+gpr_uint32 grpc_call_test_only_get_encodings_accepted_by_peer(grpc_call *call);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_INTERNAL_CORE_SURFACE_CALL_TEST_ONLY_H */
diff --git a/test/core/end2end/tests/compressed_payload.c b/test/core/end2end/tests/compressed_payload.c
index a4614a2aba4b15d7cbfe52fc79b6b2bcfde52d4e..f321fe1e7c7f8f09769e64dab29394912f336172 100644
--- a/test/core/end2end/tests/compressed_payload.c
+++ b/test/core/end2end/tests/compressed_payload.c
@@ -46,7 +46,7 @@
 #include "test/core/end2end/cq_verifier.h"
 #include "src/core/channel/channel_args.h"
 #include "src/core/channel/compress_filter.h"
-#include "src/core/surface/call.h"
+#include "src/core/surface/call_test_only.h"
 
 enum { TIMEOUT = 200000 };
 
@@ -196,12 +196,13 @@ static void request_with_payload_template(
   cq_expect_completion(cqv, tag(101), 1);
   cq_verify(cqv);
 
-  GPR_ASSERT(GPR_BITCOUNT(grpc_call_get_encodings_accepted_by_peer(s)) == 3);
-  GPR_ASSERT(GPR_BITGET(grpc_call_get_encodings_accepted_by_peer(s),
+  GPR_ASSERT(
+      GPR_BITCOUNT(grpc_call_test_only_get_encodings_accepted_by_peer(s)) == 3);
+  GPR_ASSERT(GPR_BITGET(grpc_call_test_only_get_encodings_accepted_by_peer(s),
                         GRPC_COMPRESS_NONE) != 0);
-  GPR_ASSERT(GPR_BITGET(grpc_call_get_encodings_accepted_by_peer(s),
+  GPR_ASSERT(GPR_BITGET(grpc_call_test_only_get_encodings_accepted_by_peer(s),
                         GRPC_COMPRESS_DEFLATE) != 0);
-  GPR_ASSERT(GPR_BITGET(grpc_call_get_encodings_accepted_by_peer(s),
+  GPR_ASSERT(GPR_BITGET(grpc_call_test_only_get_encodings_accepted_by_peer(s),
                         GRPC_COMPRESS_GZIP) != 0);
 
   op = ops;
diff --git a/test/cpp/interop/client_helper.h b/test/cpp/interop/client_helper.h
index 0221df93db5a715bd93781b2077297d1a64014b1..ace193042ee39b1ed88a4226773e4257a678e13d 100644
--- a/test/cpp/interop/client_helper.h
+++ b/test/cpp/interop/client_helper.h
@@ -38,7 +38,7 @@
 
 #include <grpc++/channel.h>
 
-#include "src/core/surface/call.h"
+#include "src/core/surface/call_test_only.h"
 
 namespace grpc {
 namespace testing {
@@ -57,11 +57,11 @@ class InteropClientContextInspector {
 
   // Inspector methods, able to peek inside ClientContext, follow.
   grpc_compression_algorithm GetCallCompressionAlgorithm() const {
-    return grpc_call_get_compression_algorithm(context_.call_);
+    return grpc_call_test_only_get_compression_algorithm(context_.call_);
   }
 
   gpr_uint32 GetMessageFlags() const {
-    return grpc_call_get_message_flags(context_.call_);
+    return grpc_call_test_only_get_message_flags(context_.call_);
   }
 
  private:
diff --git a/test/cpp/interop/server_helper.cc b/test/cpp/interop/server_helper.cc
index 4570750846674f276d0444f8ccbe782f0c8648f2..5138a38170a0797fcd2b77360a66afc45b4a8ca9 100644
--- a/test/cpp/interop/server_helper.cc
+++ b/test/cpp/interop/server_helper.cc
@@ -38,7 +38,7 @@
 #include <gflags/gflags.h>
 #include <grpc++/security/server_credentials.h>
 
-#include "src/core/surface/call.h"
+#include "src/core/surface/call_test_only.h"
 #include "test/core/end2end/data/ssl_test_data.h"
 
 DECLARE_bool(use_tls);
@@ -65,11 +65,11 @@ InteropServerContextInspector::InteropServerContextInspector(
 
 grpc_compression_algorithm
 InteropServerContextInspector::GetCallCompressionAlgorithm() const {
-  return grpc_call_get_compression_algorithm(context_.call_);
+  return grpc_call_test_only_get_compression_algorithm(context_.call_);
 }
 
 gpr_uint32 InteropServerContextInspector::GetEncodingsAcceptedByClient() const {
-  return grpc_call_get_encodings_accepted_by_peer(context_.call_);
+  return grpc_call_test_only_get_encodings_accepted_by_peer(context_.call_);
 }
 
 std::shared_ptr<const AuthContext>
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 5658a102d75d36deccc0e1aaa99210a32c3253a2..5fd3ee70d635517f8678b6f851a20b98a5333488 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -858,6 +858,7 @@ src/core/statistics/census_rpc_stats.h \
 src/core/surface/api_trace.h \
 src/core/surface/byte_buffer_queue.h \
 src/core/surface/call.h \
+src/core/surface/call_test_only.h \
 src/core/surface/channel.h \
 src/core/surface/completion_queue.h \
 src/core/surface/event_string.h \
diff --git a/tools/run_tests/sources_and_headers.json b/tools/run_tests/sources_and_headers.json
index 1ceff15a3be19ad9625bd90a0650f9b07652b58b..76d66ed7a07a81052fe74dc641249df75d26ba0d 100644
--- a/tools/run_tests/sources_and_headers.json
+++ b/tools/run_tests/sources_and_headers.json
@@ -12365,6 +12365,7 @@
       "src/core/surface/api_trace.h", 
       "src/core/surface/byte_buffer_queue.h", 
       "src/core/surface/call.h", 
+      "src/core/surface/call_test_only.h", 
       "src/core/surface/channel.h", 
       "src/core/surface/completion_queue.h", 
       "src/core/surface/event_string.h", 
@@ -12607,6 +12608,7 @@
       "src/core/surface/call.h", 
       "src/core/surface/call_details.c", 
       "src/core/surface/call_log_batch.c", 
+      "src/core/surface/call_test_only.h", 
       "src/core/surface/channel.c", 
       "src/core/surface/channel.h", 
       "src/core/surface/channel_connectivity.c", 
@@ -12861,6 +12863,7 @@
       "src/core/surface/api_trace.h", 
       "src/core/surface/byte_buffer_queue.h", 
       "src/core/surface/call.h", 
+      "src/core/surface/call_test_only.h", 
       "src/core/surface/channel.h", 
       "src/core/surface/completion_queue.h", 
       "src/core/surface/event_string.h", 
@@ -13073,6 +13076,7 @@
       "src/core/surface/call.h", 
       "src/core/surface/call_details.c", 
       "src/core/surface/call_log_batch.c", 
+      "src/core/surface/call_test_only.h", 
       "src/core/surface/channel.c", 
       "src/core/surface/channel.h", 
       "src/core/surface/channel_connectivity.c", 
diff --git a/vsprojects/vcxproj/grpc/grpc.vcxproj b/vsprojects/vcxproj/grpc/grpc.vcxproj
index 183edbc05bf7cd124537104857d68049da4de391..88b883f67cfc519d0c0f8c5697fea7be4671fa7c 100644
--- a/vsprojects/vcxproj/grpc/grpc.vcxproj
+++ b/vsprojects/vcxproj/grpc/grpc.vcxproj
@@ -344,6 +344,7 @@
     <ClInclude Include="..\..\..\src\core\surface\api_trace.h" />
     <ClInclude Include="..\..\..\src\core\surface\byte_buffer_queue.h" />
     <ClInclude Include="..\..\..\src\core\surface\call.h" />
+    <ClInclude Include="..\..\..\src\core\surface\call_test_only.h" />
     <ClInclude Include="..\..\..\src\core\surface\channel.h" />
     <ClInclude Include="..\..\..\src\core\surface\completion_queue.h" />
     <ClInclude Include="..\..\..\src\core\surface\event_string.h" />
diff --git a/vsprojects/vcxproj/grpc/grpc.vcxproj.filters b/vsprojects/vcxproj/grpc/grpc.vcxproj.filters
index 66ce9ca05be6387db553db3a0be7571d201cf373..1a46ac8e34b79036b9be797bb278f767b8fc197a 100644
--- a/vsprojects/vcxproj/grpc/grpc.vcxproj.filters
+++ b/vsprojects/vcxproj/grpc/grpc.vcxproj.filters
@@ -743,6 +743,9 @@
     <ClInclude Include="..\..\..\src\core\surface\call.h">
       <Filter>src\core\surface</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\..\src\core\surface\call_test_only.h">
+      <Filter>src\core\surface</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\..\src\core\surface\channel.h">
       <Filter>src\core\surface</Filter>
     </ClInclude>
diff --git a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj
index b527179f9f314935c5bac6aade3c72617646481c..cddd00374b2d2c1d3d80512873e3497c571aa9cc 100644
--- a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj
+++ b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj
@@ -323,6 +323,7 @@
     <ClInclude Include="..\..\..\src\core\surface\api_trace.h" />
     <ClInclude Include="..\..\..\src\core\surface\byte_buffer_queue.h" />
     <ClInclude Include="..\..\..\src\core\surface\call.h" />
+    <ClInclude Include="..\..\..\src\core\surface\call_test_only.h" />
     <ClInclude Include="..\..\..\src\core\surface\channel.h" />
     <ClInclude Include="..\..\..\src\core\surface\completion_queue.h" />
     <ClInclude Include="..\..\..\src\core\surface\event_string.h" />
diff --git a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
index 7be3c9ec93b65d5cfd028d9f04de7f987e01d998..01e0d8daddea8ddac0725b3814bc39fafb7fc68e 100644
--- a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
+++ b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
@@ -641,6 +641,9 @@
     <ClInclude Include="..\..\..\src\core\surface\call.h">
       <Filter>src\core\surface</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\..\src\core\surface\call_test_only.h">
+      <Filter>src\core\surface</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\..\src\core\surface\channel.h">
       <Filter>src\core\surface</Filter>
     </ClInclude>