Extend integration test to test sequence of FUSE operation

Original FUSE integration test has limited capabilities. To test more
situations, the new integration test framework introduces a protocol
to communicate between testing thread and the FUSE server. In summary,
this change includes:

1. Remove CompareResult() and break SetExpected() into
   SetServerResponse() and GetServerActualRequest(). We no longer set
   up an expected request because we want to retrieve the actual FUSE
   request made to the FUSE server and check in the testing thread.

2. Declare a serial buffer data structure to save the received requests
   and expected responses sequentially. The data structure contains a
   cursor to indicate the progress of accessing. This change makes
   sequential SetServerResponse() and GetServerActualRequest() possible.

3. Replace 2 single directional pipes with 1 bi-directional socketpair.
   A protocol which starts with FuseTestCmd is used between the testing
   thread and the FUSE server to provide various functionality.

Fixes #3405

1 files changed, 34 insertions, 51 deletions

diff --git a/test/fuse/linux/stat_test.cc b/test/fuse/linux/stat_test.cc
index 172e09867..c2e5bd1cf 100644
--- a/test/fuse/linux/stat_test.cc
+++ b/test/fuse/linux/stat_test.cc
@@ -33,20 +33,6 @@ namespace {
 
 class StatTest : public FuseTest {
  public:
-  bool CompareRequest(void* expected_mem, size_t expected_len, void* real_mem,
-                      size_t real_len) override {
-    if (expected_len != real_len) return false;
-    struct fuse_in_header* real_header =
-        reinterpret_cast<fuse_in_header*>(real_mem);
-
-    if (real_header->opcode != FUSE_GETATTR) {
-      std::cerr << "expect header opcode " << FUSE_GETATTR << " but got "
-                << real_header->opcode << std::endl;
-      return false;
-    }
-    return true;
-  }
-
   bool StatsAreEqual(struct stat expected, struct stat actual) {
     // device number will be dynamically allocated by kernel, we cannot know
     // in advance
@@ -56,25 +42,9 @@ class StatTest : public FuseTest {
 };
 
 TEST_F(StatTest, StatNormal) {
-  struct iovec iov_in[2];
-  struct iovec iov_out[2];
-
-  struct fuse_in_header in_header = {
-      .len = sizeof(struct fuse_in_header) + sizeof(struct fuse_getattr_in),
-      .opcode = FUSE_GETATTR,
-      .unique = 4,
-      .nodeid = 1,
-      .uid = 0,
-      .gid = 0,
-      .pid = 4,
-      .padding = 0,
-  };
-  struct fuse_getattr_in in_payload = {0};
-  iov_in[0].iov_len = sizeof(in_header);
-  iov_in[0].iov_base = &in_header;
-  iov_in[1].iov_len = sizeof(in_payload);
-  iov_in[1].iov_base = &in_payload;
-
+  // Set up fixture.
+  std::vector<struct iovec> iov_in(2);
+  std::vector<struct iovec> iov_out(2);
   mode_t expected_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
   struct timespec atime = {.tv_sec = 1595436289, .tv_nsec = 134150844};
   struct timespec mtime = {.tv_sec = 1595436290, .tv_nsec = 134150845};
@@ -82,7 +52,6 @@ TEST_F(StatTest, StatNormal) {
   struct fuse_out_header out_header = {
       .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
       .error = 0,
-      .unique = 4,
   };
   struct fuse_attr attr = {
       .ino = 1,
@@ -109,11 +78,13 @@ TEST_F(StatTest, StatNormal) {
   iov_out[1].iov_len = sizeof(out_payload);
   iov_out[1].iov_base = &out_payload;
 
-  SetExpected(iov_in, 2, iov_out, 2);
+  SetServerResponse(FUSE_GETATTR, iov_out);
 
+  // Do integration test.
   struct stat stat_buf;
   EXPECT_THAT(stat(mount_point_.path().c_str(), &stat_buf), SyscallSucceeds());
 
+  // Check filesystem operation result.
   struct stat expected_stat = {
       .st_ino = attr.ino,
       .st_nlink = attr.nlink,
@@ -129,38 +100,50 @@ TEST_F(StatTest, StatNormal) {
       .st_ctim = ctime,
   };
   EXPECT_TRUE(StatsAreEqual(stat_buf, expected_stat));
-  WaitCompleted();
-}
-
-TEST_F(StatTest, StatNotFound) {
-  struct iovec iov_in[2];
-  struct iovec iov_out[2];
 
-  struct fuse_in_header in_header = {
-      .len = sizeof(struct fuse_in_header) + sizeof(struct fuse_getattr_in),
-      .opcode = FUSE_GETATTR,
-      .unique = 4,
-  };
-  struct fuse_getattr_in in_payload = {0};
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_getattr_in in_payload;
   iov_in[0].iov_len = sizeof(in_header);
   iov_in[0].iov_base = &in_header;
   iov_in[1].iov_len = sizeof(in_payload);
   iov_in[1].iov_base = &in_payload;
 
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.opcode, FUSE_GETATTR);
+  EXPECT_EQ(in_payload.getattr_flags, 0);
+  EXPECT_EQ(in_payload.fh, 0);
+}
+
+TEST_F(StatTest, StatNotFound) {
+  // Set up fixture.
+  std::vector<struct iovec> iov_in(2);
+  std::vector<struct iovec> iov_out(1);
   struct fuse_out_header out_header = {
       .len = sizeof(struct fuse_out_header),
       .error = -ENOENT,
-      .unique = 4,
   };
   iov_out[0].iov_len = sizeof(out_header);
   iov_out[0].iov_base = &out_header;
+  SetServerResponse(FUSE_GETATTR, iov_out);
 
-  SetExpected(iov_in, 2, iov_out, 1);
-
+  // Do integration test.
   struct stat stat_buf;
   EXPECT_THAT(stat(mount_point_.path().c_str(), &stat_buf),
               SyscallFailsWithErrno(ENOENT));
-  WaitCompleted();
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_getattr_in in_payload;
+  iov_in[0].iov_len = sizeof(in_header);
+  iov_in[0].iov_base = &in_header;
+  iov_in[1].iov_len = sizeof(in_payload);
+  iov_in[1].iov_base = &in_payload;
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.opcode, FUSE_GETATTR);
+  EXPECT_EQ(in_payload.getattr_flags, 0);
+  EXPECT_EQ(in_payload.fh, 0);
 }
 
 }  // namespace