Print more helpful error message when X server fails to start

Usually, xorg-gtest requires the dummy video driver. It also requires an
X server at least version 1.12, or to be run as root when testing with a
previous X server. Print this information when the server fails to
start, and point the user to the log file for further details.

Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
Reviewed-By: Christopher Halse Rogers <christopher.halse.rogers@canonical.com>

1 files changed, 12 insertions, 6 deletions

diff --git a/src/environment.cpp b/src/environment.cpp
index 3da27cb..f4bb9e1 100644
--- a/src/environment.cpp
+++ b/src/environment.cpp
@@ -122,16 +122,22 @@ void xorg::testing::Environment::SetUp() {
 
     int status;
     int pid = waitpid(d_->process.Pid(), &status, WNOHANG);
-    if (pid == d_->process.Pid())
-      throw std::runtime_error("Dummy X server failed to start, did you run as "
-                               "root?");
-    else if (pid == 0)
+    if (pid == d_->process.Pid()) {
+      std::string message;
+      message += "X server failed to start. Ensure that the \"dummy\" video "
+                 "driver is installed. If the X.org server is older than 1.12, "
+                 "tests will need to be run as root. Check ";
+      message += d_->path_to_log_file;
+      message += " for any errors";
+      throw std::runtime_error(message);
+    } else if (pid == 0) {
       sleep(1); /* Give the dummy X server some time to start */
-    else if (pid == -1)
+    } else if (pid == -1) {
       throw std::runtime_error("Could not get status of dummy X server "
                                "process");
-    else
+    } else {
       throw std::runtime_error("Invalid child PID returned by Process::Wait()");
+    }
   }
 
   throw std::runtime_error("Unable to open connection to dummy X server");