tests: Skip some tests if we don't have Xvfb or setxkbmap

The keyboard test relies on both of those programs, the network
panel test on Xvfb. Where we don't have those programs installed (e.g. a
pure Wayland session) we cannot run the test.

tests/keyboard/meson.build

@@ -1,35 +1,35 @@
-find_program('setxkbmap')
+if setxkbmap.found() and Xvfb.found()
+  test_units = [
+    'test-keyboard-shortcuts'
+  ]
 
-test_units = [
-  'test-keyboard-shortcuts'
-]
+  env = [
+    'G_MESSAGES_DEBUG=all',
+            'BUILDDIR=' + meson.current_build_dir(),
+        'TOP_BUILDDIR=' + meson.project_build_root(),
+  # Disable ATK, this should not be required but it caused CI failures -- 2018-12-07
+        'NO_AT_BRIDGE=1'
+  ]
+  cflags = [
+    '-DTEST_SRCDIR="@0@"'.format(meson.current_source_dir())
+  ]
+  includes = [top_inc, include_directories('../../panels/keyboard')]
 
-env = [
-  'G_MESSAGES_DEBUG=all',
-          'BUILDDIR=' + meson.current_build_dir(),
-      'TOP_BUILDDIR=' + meson.project_build_root(),
-# Disable ATK, this should not be required but it caused CI failures -- 2018-12-07
-      'NO_AT_BRIDGE=1'
-]
-cflags = [
-  '-DTEST_SRCDIR="@0@"'.format(meson.current_source_dir())
-]
-includes = [top_inc, include_directories('../../panels/keyboard')]
+  foreach unit: test_units
+    exe = executable(
+                      unit,
+             [unit + '.c'],
+             dependencies : common_deps,
+      include_directories : includes,
+                link_with : [keyboard_panel_lib],
+                   c_args : cflags
+    )
+  endforeach
 
-foreach unit: test_units
-  exe = executable(
-                    unit,
-           [unit + '.c'],
-           dependencies : common_deps,
-    include_directories : includes,
-              link_with : [keyboard_panel_lib],
-                 c_args : cflags
+  test(
+    'test-keyboard',
+    find_program('test-keyboard.py'),
+        env : env,
+    timeout : 60
   )
-endforeach
-
-test(
-  'test-keyboard',
-  find_program('test-keyboard.py'),
-      env : env,
-  timeout : 60
-)
+endif

tests/meson.build

@@ -1,3 +1,6 @@
+setxkbmap = find_program('setxkbmap', required: false)
+Xvfb = find_program('Xvfb', required: false)
+
 subdir('common')
 #subdir('datetime')
 if host_is_linux

tests/network/meson.build

@@ -8,15 +8,6 @@ cflags = [
   '-DTEST_NM_SERVICE="@0@"'.format(join_paths(meson.project_source_root(), 'tests', 'network', 'nm-utils', 'test-networkmanager-service.py')),
 ]
 
-exe = executable(
-  'test-network-panel',
-  ['test-network-panel.c', 'cc-test-window.c', 'nm-utils/nm-test-utils-impl.c'],
-  include_directories : includes + [common_inc],
-         dependencies : common_deps + network_manager_deps + [libtestshell_dep],
-            link_with : [network_panel_lib],
-               c_args : cflags
-)
-
 envs = [
   'G_MESSAGES_DEBUG=all',
           'BUILDDIR=' + meson.current_build_dir(),
@@ -26,12 +17,23 @@ envs = [
       'GTK_A11Y=none',
 ]
 
-test(
-  'test-network-panel',
-  find_program('test-network-panel.py'),
-      env : envs,
-  timeout : 60
-)
+if Xvfb.found()
+  exe = executable(
+    'test-network-panel',
+    ['test-network-panel.c', 'cc-test-window.c', 'nm-utils/nm-test-utils-impl.c'],
+    include_directories : includes + [common_inc],
+           dependencies : common_deps + network_manager_deps + [libtestshell_dep],
+              link_with : [network_panel_lib],
+                 c_args : cflags
+  )
+
+  test(
+    'test-network-panel',
+    find_program('test-network-panel.py'),
+        env : envs,
+    timeout : 60
+  )
+endif
 
 exe = executable(
   'test-wifi-panel-text',