Wrap test with xvfb-run in meson

meson.build

@@ -689,11 +689,17 @@ if get_option('enable-x11')
         executable('test-x11', 'test/x11.c', dependencies: x11_test_dep),
         env: test_env,
     )
-    test(
-        'x11comp',
-        executable('test-x11comp', 'test/x11comp.c', dependencies: x11_test_dep),
-        env: test_env,
-    )
+    x11comp = executable('test-x11comp', 'test/x11comp.c', dependencies: x11_test_dep)
+    xvfb = find_program('xvfb-run', required: false)
+    if xvfb.found()
+        test(
+            'x11comp',
+            xvfb,
+            args: ['--auto-servernum', x11comp],
+            depends: x11comp,
+            env: test_env,
+        )
+    endif
 endif
 if get_option('enable-xkbregistry')
     test(

test/x11comp.c

@@ -25,10 +25,7 @@
 
 #include <stdio.h>
 #include <spawn.h>
-#include <unistd.h>
 #include <assert.h>
-#include <signal.h>
-#include <sys/types.h>
 #include <sys/wait.h>
 
 #include "test.h"
@@ -45,60 +42,33 @@ main(void)
     char display[512];
     char *xkb_path;
     char *original, *dump;
-    char *envp[] = { NULL };
-    char *xvfb_argv[] = {
-        (char *) "Xvfb", display, NULL
-    };
-    pid_t xvfb_pid = 0;
+    // char *envp[] = { NULL };
+
     char *xkbcomp_argv[] = {
         (char *) "xkbcomp", (char *) "-I", NULL /* xkb_path */, display, NULL
     };
     pid_t xkbcomp_pid;
 
+    // [FIXME] debugging
+    const char* s = getenv("XAUTHORITY");
+    fprintf(stderr, "XAUTHORITY: %s\n", (s != NULL) ? s : "getenv returned NULL");
+    char xauthority[512];
+    snprintf(xauthority, sizeof(xauthority), "XAUTHORITY=%s", s);
+
+    s = getenv("DISPLAY");
+    fprintf(stderr, "DISPLAY: %s\n", (s != NULL) ? s : "getenv returned NULL");
+    char *envp[] = { xauthority, NULL };
+
     char *xhost = NULL;
-    int xdpy_current;
-    int xdpy_candidate;
-
-    /*
-     * What all of this mess does is:
-     * 1. Launch Xvfb on available DISPLAY.
-     * 2. Make an xcb connection to this display.
-     * 3. Launch xkbcomp to change the keymap of the new display (doing
-     *    this programmatically is major work [which we may yet do some
-     *    day for xkbcommon-x11] so we use xkbcomp for now).
-     * 4. Download the keymap back from the display using xkbcommon-x11.
-     * 5. Compare received keymap to the uploaded keymap.
-     * 6. Kill the server & clean up.
-     */
-
-    ret = xcb_parse_display(NULL, &xhost, &xdpy_current, NULL);
+    int xdisplay;
+
+    /* Get display from environment ($DISPLAY) */
+    ret = xcb_parse_display(NULL, &xhost, &xdisplay, NULL);
     assert(ret != 0);
-    /*
-     * IANA assigns TCP port numbers from 6000 through 6063 to X11
-     * clients.  In addition, the current XCB implementaion shows
-     * that, when an X11 client tries to establish a TCP connetion,
-     * the port number needed is specified by adding 6000 to a given
-     * display number.  So, one of reasonable ranges of xdpy_candidate
-     * is [0, 63].
-     */
-    for (xdpy_candidate = 63; xdpy_candidate >= 0; xdpy_candidate--) {
-        if (xdpy_candidate == xdpy_current) {
-            continue;
-        }
-        snprintf(display, sizeof(display), "%s:%d", xhost, xdpy_candidate);
-        ret = posix_spawnp(&xvfb_pid, "Xvfb", NULL, NULL, xvfb_argv, envp);
-        if (ret == 0) {
-            break;
-        }
-    }
+    snprintf(display, sizeof(display), "%s:%d", xhost, xdisplay);
     free(xhost);
-    if (ret != 0) {
-        ret = SKIP_TEST;
-        goto err_ctx;
-    }
 
-    /* Wait for Xvfb fully waking up to accept a connection from a client. */
-    sleep(1);
+    fprintf(stderr, "parsed DISPLAY: “%s”\n", display);
 
     conn = xcb_connect(display, NULL);
     if (xcb_connection_has_error(conn)) {
@@ -162,9 +132,6 @@ main(void)
 err_xcb:
     xcb_disconnect(conn);
 err_xvfd:
-    if (xvfb_pid > 0)
-        kill(xvfb_pid, SIGTERM);
-err_ctx:
     xkb_context_unref(ctx);
     return ret;
 }