Make binary role tests more robust

t/CanStartBinary.t

@@ -2,52 +2,66 @@
 
 use strict;
 use warnings;
+use File::Which qw/which/;
 use Selenium::Firefox::Binary;
 use Selenium::Chrome;
 use Selenium::PhantomJS;
 use Selenium::Firefox;
 use Test::More;
 
-unless( $ENV{RELEASE_TESTING} ) {
+unless ( $ENV{RELEASE_TESTING} ) {
     plan skip_all => "Author tests not required for installation.";
 }
 
 PHANTOMJS: {
-    my $version = `phantomjs -v` // '';
-    chomp $version;
+  SKIP: {
+        my $has_phantomjs = Selenium::CanStartBinary::_find_executable('phantomjs');
+        skip 'Phantomjs binary not found in path', 3
+          unless $has_phantomjs;
 
-    skip 'PhantomJS binary not found in path', 3
-      unless is_proper_phantomjs_available($version);
+        my $version = `phantomjs -v` // '';
+        chomp $version;
 
-    my $phantom = Selenium::PhantomJS->new;
-    is( $phantom->browser_name, 'phantomjs', 'binary phantomjs is okay');
-    isnt( $phantom->port, 4444, 'phantomjs can start up its own binary');
+        skip 'PhantomJS binary not found in path', 3
+          unless is_proper_phantomjs_available($version);
 
-    ok( Selenium::CanStartBinary::probe_port( $phantom->port ), 'the phantomjs binary is listening on its port');
+        my $phantom = Selenium::PhantomJS->new;
+        is( $phantom->browser_name, 'phantomjs', 'binary phantomjs is okay');
+        isnt( $phantom->port, 4444, 'phantomjs can start up its own binary');
+
+        ok( Selenium::CanStartBinary::probe_port( $phantom->port ), 'the phantomjs binary is listening on its port');
+    }
 }
 
 CHROME: {
-    # TODO: fix this test, as it's a hack that depends entirely on the
-    # node module protractor's included `webdriver-manager` binary.
-    $ENV{PATH} .= ':/usr/local/lib/node_modules/protractor/selenium';
+  SKIP: {
+        my $has_chromedriver = Selenium::CanStartBinary::_find_executable('chromedriver');
+        skip 'Chrome binary not found in path', 3
+          unless $has_chromedriver;
 
-    my $chrome = Selenium::Chrome->new;
-    ok( $chrome->browser_name eq 'chrome', 'convenience chrome is okay' );
-    isnt( $chrome->port, 4444, 'chrome can start up its own binary');
+        my $chrome = Selenium::Chrome->new;
+        ok( $chrome->browser_name eq 'chrome', 'convenience chrome is okay' );
+        isnt( $chrome->port, 4444, 'chrome can start up its own binary');
 
-    ok( Selenium::CanStartBinary::probe_port( $chrome->port ), 'the chrome binary is listening on its port');
+        ok( Selenium::CanStartBinary::probe_port( $chrome->port ), 'the chrome binary is listening on its port');
+    }
 }
 
 FIREFOX: {
-    my $binary = Selenium::Firefox::Binary::firefox_path();
-    ok(-x $binary, 'we can find some sort of firefox');
-
     my $command = Selenium::CanStartBinary::_construct_command('firefox', 1234);
     ok($command =~ /firefox -no-remote/, 'firefox command has proper args');
 
-    my $firefox = Selenium::Firefox->new;
-    isnt( $firefox->port, 4444, 'firefox can start up its own binary');
-    ok( Selenium::CanStartBinary::probe_port( $firefox->port ), 'the firefox binary is listening on its port');
+  SKIP: {
+        my $binary = Selenium::Firefox::Binary::firefox_path();
+        skip 'Firefox binary not found in path', 3
+          unless $binary;
+
+        ok(-x $binary, 'we can find some sort of firefox');
+
+        my $firefox = Selenium::Firefox->new;
+        isnt( $firefox->port, 4444, 'firefox can start up its own binary');
+        ok( Selenium::CanStartBinary::probe_port( $firefox->port ), 'the firefox binary is listening on its port');
+    }
 }
 
 sub is_proper_phantomjs_available {