From 23d88e0e039ab4abbb001cb99f448693feecac56 Mon Sep 17 00:00:00 2001
From: ridiculousfish <corydoras@ridiculousfish.com>
Date: Sat, 6 Apr 2019 22:22:11 -0700
Subject: [PATCH] Add fish_test_helper executable

In tests we would like to arrange for an executable to invoke certain
system calls, e.g. to claim or relinquish control of the terminal. This is
annoying to do portably via e.g. perl. fish_test_helper is a little
program where we can add custom commands to make it act in certain ways.
---
 CMakeLists.txt           |  3 +++
 cmake/Tests.cmake        |  5 ++++-
 src/fish_test_helper.cpp | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 src/fish_test_helper.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 443a6640b..d7250acd3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -162,6 +162,9 @@ ADD_EXECUTABLE(fish_key_reader
                src/fish_key_reader.cpp src/print_help.cpp)
 FISH_LINK_DEPS(fish_key_reader)
 
+# A helper for running tests.
+ADD_EXECUTABLE(fish_test_helper src/fish_test_helper.cpp)
+
 # Set up tests.
 INCLUDE(cmake/Tests.cmake)
 
diff --git a/cmake/Tests.cmake b/cmake/Tests.cmake
index cab0158e9..7b398744e 100644
--- a/cmake/Tests.cmake
+++ b/cmake/Tests.cmake
@@ -44,14 +44,17 @@ ADD_DEPENDENCIES(test test_low_level tests_dir)
 
 # Make the directory in which to run tests.
 # Also symlink fish to where the tests expect it to be.
+# Lastly put fish_test_helper there too.
 ADD_CUSTOM_TARGET(tests_buildroot_target
                   COMMAND ${CMAKE_COMMAND} -E make_directory ${TEST_INSTALL_DIR}
                   COMMAND DESTDIR=${TEST_INSTALL_DIR} ${CMAKE_COMMAND}
                           --build ${CMAKE_CURRENT_BINARY_DIR} --target install
+                  COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_BINARY_DIR}/fish_test_helper
+                          ${TEST_INSTALL_DIR}/${CMAKE_INSTALL_PREFIX}/bin
                   COMMAND ${CMAKE_COMMAND} -E create_symlink
                           ${TEST_INSTALL_DIR}/${CMAKE_INSTALL_PREFIX}
                           ${TEST_ROOT_DIR}
-                  DEPENDS fish)
+                  DEPENDS fish fish_test_helper)
 
 IF(NOT FISH_IN_TREE_BUILD)
   # We need to symlink share/functions for the tests.
diff --git a/src/fish_test_helper.cpp b/src/fish_test_helper.cpp
new file mode 100644
index 000000000..50f3bca7a
--- /dev/null
+++ b/src/fish_test_helper.cpp
@@ -0,0 +1,32 @@
+// fish_test_helper is a little program with no fish dependencies that acts like certain other
+// programs, allowing fish to test its behavior.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static void become_foreground_then_print_stderr() {
+    if (tcsetpgrp(STDOUT_FILENO, getpgrp()) < 0) {
+        perror("tcsetgrp");
+        exit(EXIT_FAILURE);
+    }
+    usleep(1000000 / 4);  //.25 secs
+    fprintf(stderr, "become_foreground_then_print_stderr done\n");
+}
+
+int main(int argc, char *argv[]) {
+    if (argc <= 1) {
+        fprintf(stderr, "No commands given.");
+        return 0;
+    }
+    for (int i = 1; i < argc; i++) {
+        if (!strcmp(argv[i], "become_foreground_then_print_stderr")) {
+            become_foreground_then_print_stderr();
+        } else {
+            fprintf(stderr, "%s: Unknown command: %s\n", argv[0], argv[i]);
+            return EXIT_FAILURE;
+        }
+    }
+    return 0;
+}