diff --git a/t/mojo/subprocess.t b/t/mojo/subprocess.t
index 71521b23fe..c724c4dbd7 100644
--- a/t/mojo/subprocess.t
+++ b/t/mojo/subprocess.t
@@ -12,248 +12,264 @@ use Mojo::IOLoop::Subprocess;
 use Mojo::Promise;
 use Mojo::File qw(tempfile);
 
-# Huge result
-my ($fail, $result, @start);
-my $subprocess = Mojo::IOLoop::Subprocess->new;
-$subprocess->on(spawn => sub { push @start, shift->pid });
-$subprocess->run(
-  sub { shift->pid . $$ . ('x' x 100000) },
-  sub {
-    my ($subprocess, $err, $two) = @_;
-    $fail = $err;
-    $result .= $two;
-  }
-);
-$result = $$;
-ok !$subprocess->pid, 'no process id available yet';
-is $subprocess->exit_code, undef, 'no exit code';
-Mojo::IOLoop->start;
-ok $subprocess->pid, 'process id available';
-is $subprocess->exit_code, 0, 'zero exit code';
-ok !$fail, 'no error';
-is $result, $$ . 0 . $subprocess->pid . ('x' x 100000), 'right result';
-is_deeply \@start, [$subprocess->pid], 'spawn event has been emitted once';
+subtest 'Huge result' => sub {
+  my ($fail, $result, @start);
+  my $subprocess = Mojo::IOLoop::Subprocess->new;
+  $subprocess->on(spawn => sub { push @start, shift->pid });
+  $subprocess->run(
+    sub { shift->pid . $$ . ('x' x 100000) },
+    sub {
+      my ($subprocess, $err, $two) = @_;
+      $fail = $err;
+      $result .= $two;
+    }
+  );
 
-# Custom event loop
-($fail, $result) = ();
-my $loop = Mojo::IOLoop->new;
-$loop->subprocess(
-  sub {'♥'},
-  sub {
-    my ($subprocess, $err, @results) = @_;
-    $fail   = $err;
-    $result = \@results;
-  }
-);
-$loop->start;
-ok !$fail, 'no error';
-is_deeply $result, ['♥'], 'right structure';
+  $result = $$;
+  ok !$subprocess->pid, 'no process id available yet';
+  is $subprocess->exit_code, undef, 'no exit code';
+  Mojo::IOLoop->start;
+  ok $subprocess->pid, 'process id available';
+  is $subprocess->exit_code, 0, 'zero exit code';
+  ok !$fail, 'no error';
+  is $result, $$ . 0 . $subprocess->pid . ('x' x 100000), 'right result';
+  is_deeply \@start, [$subprocess->pid], 'spawn event has been emitted once';
+};
 
-# Multiple return values
-($fail, $result) = ();
-$subprocess = Mojo::IOLoop::Subprocess->new;
-$subprocess->run(
-  sub { return '♥', [{two => 2}], 3 },
-  sub {
-    my ($subprocess, $err, @results) = @_;
-    $fail   = $err;
-    $result = \@results;
-  }
-);
-Mojo::IOLoop->start;
-ok !$fail, 'no error';
-is_deeply $result, ['♥', [{two => 2}], 3], 'right structure';
+subtest 'Custom event loop' => sub {
+  my ($fail, $result);
+  my $loop = Mojo::IOLoop->new;
+  $loop->subprocess(
+    sub {'♥'},
+    sub {
+      my ($subprocess, $err, @results) = @_;
+      $fail   = $err;
+      $result = \@results;
+    }
+  );
+  $loop->start;
+  ok !$fail, 'no error';
+  is_deeply $result, ['♥'], 'right structure';
+};
 
-# Promises
-$result     = [];
-$subprocess = Mojo::IOLoop::Subprocess->new;
-is $subprocess->exit_code, undef, 'no exit code';
-$subprocess->run_p(sub { return '♥', [{two => 2}], 3 })->then(sub { $result = [@_] })->wait;
-is_deeply $result, ['♥', [{two => 2}], 3], 'right structure';
-$fail       = undef;
-$subprocess = Mojo::IOLoop::Subprocess->new;
-$subprocess->run_p(sub { die 'Whatever' })->catch(sub { $fail = shift })->wait;
-is $subprocess->exit_code, 0, 'zero exit code';
-like $fail, qr/Whatever/, 'right error';
-$result = [];
-Mojo::IOLoop->subprocess->run_p(sub { return '♥' })->then(sub { $result = [@_] })->wait;
-is_deeply $result, ['♥'], 'right structure';
+subtest 'Multiple return values' => sub {
+  my ($fail, $result);
+  my $subprocess = Mojo::IOLoop::Subprocess->new;
+  $subprocess->run(
+    sub { return '♥', [{two => 2}], 3 },
+    sub {
+      my ($subprocess, $err, @results) = @_;
+      $fail   = $err;
+      $result = \@results;
+    }
+  );
+  Mojo::IOLoop->start;
+  ok !$fail, 'no error';
+  is_deeply $result, ['♥', [{two => 2}], 3], 'right structure';
+};
 
-# Event loop in subprocess
-($fail, $result) = ();
-$subprocess = Mojo::IOLoop::Subprocess->new;
-$subprocess->run(
-  sub {
-    my $result;
-    Mojo::IOLoop->next_tick(sub { $result = 23 });
-    Mojo::IOLoop->start;
-    return $result;
-  },
-  sub {
-    my ($subprocess, $err, $twenty_three) = @_;
-    $fail   = $err;
-    $result = $twenty_three;
-  }
-);
-Mojo::IOLoop->start;
-ok !$fail, 'no error';
-is $result, 23, 'right result';
+subtest 'Promises' => sub {
+  my $result     = [];
+  my $subprocess = Mojo::IOLoop::Subprocess->new;
+  is $subprocess->exit_code, undef, 'no exit code';
+  $subprocess->run_p(sub { return '♥', [{two => 2}], 3 })->then(sub { $result = [@_] })->wait;
+  is_deeply $result, ['♥', [{two => 2}], 3], 'right structure';
+  my $fail;
+  $subprocess = Mojo::IOLoop::Subprocess->new;
+  $subprocess->run_p(sub { die 'Whatever' })->catch(sub { $fail = shift })->wait;
+  is $subprocess->exit_code, 0, 'zero exit code';
+  like $fail, qr/Whatever/, 'right error';
+  $result = [];
+  Mojo::IOLoop->subprocess->run_p(sub { return '♥' })->then(sub { $result = [@_] })->wait;
+  is_deeply $result, ['♥'], 'right structure';
+};
 
-# Event loop in subprocess (already running event loop)
-($fail, $result) = ();
-Mojo::IOLoop->next_tick(sub {
-  Mojo::IOLoop->subprocess(
+subtest 'Event loop in subprocess' => sub {
+  my ($fail, $result);
+  my $subprocess = Mojo::IOLoop::Subprocess->new;
+  $subprocess->run(
     sub {
       my $result;
-      my $promise = Mojo::Promise->new;
-      $promise->then(sub { $result = shift });
-      Mojo::IOLoop->next_tick(sub { $promise->resolve(25) });
-      $promise->wait;
+      Mojo::IOLoop->next_tick(sub { $result = 23 });
+      Mojo::IOLoop->start;
       return $result;
     },
     sub {
-      my ($subprocess, $err, $twenty_five) = @_;
+      my ($subprocess, $err, $twenty_three) = @_;
       $fail   = $err;
-      $result = $twenty_five;
+      $result = $twenty_three;
     }
   );
-});
-Mojo::IOLoop->start;
-ok !$fail, 'no error';
-is $result, 25, 'right result';
+  Mojo::IOLoop->start;
+  ok !$fail, 'no error';
+  is $result, 23, 'right result';
+};
 
-# Concurrent subprocesses
-($fail, $result) = ();
-my $promise  = Mojo::IOLoop->subprocess->run_p(sub {1});
-my $promise2 = Mojo::IOLoop->subprocess->run_p(sub {2});
-Mojo::Promise->all($promise, $promise2)->then(sub {
-  $result = [map { $_->[0] } @_];
-})->catch(sub { $fail = shift })->wait;
-ok !$fail, 'no error';
-is_deeply $result, [1, 2], 'right structure';
+subtest 'Event loop in subprocess (already running event loop)' => sub {
+  my ($fail, $result);
+  Mojo::IOLoop->next_tick(sub {
+    Mojo::IOLoop->subprocess(
+      sub {
+        my $result;
+        my $promise = Mojo::Promise->new;
+        $promise->then(sub { $result = shift });
+        Mojo::IOLoop->next_tick(sub { $promise->resolve(25) });
+        $promise->wait;
+        return $result;
+      },
+      sub {
+        my ($subprocess, $err, $twenty_five) = @_;
+        $fail   = $err;
+        $result = $twenty_five;
+      }
+    );
+  });
+  Mojo::IOLoop->start;
+  ok !$fail, 'no error';
+  is $result, 25, 'right result';
+};
 
-# No result
-($fail, $result) = ();
-Mojo::IOLoop::Subprocess->new->run(
-  sub {return},
-  sub {
-    my ($subprocess, $err, @results) = @_;
-    $fail   = $err;
-    $result = \@results;
-  }
-);
-Mojo::IOLoop->start;
-ok !$fail, 'no error';
-is_deeply $result, [], 'right structure';
+subtest 'Concurrent subprocesses' => sub {
+  my ($fail, $result);
+  my $promise  = Mojo::IOLoop->subprocess->run_p(sub {1});
+  my $promise2 = Mojo::IOLoop->subprocess->run_p(sub {2});
+  Mojo::Promise->all($promise, $promise2)->then(sub {
+    $result = [map { $_->[0] } @_];
+  })->catch(sub { $fail = shift })->wait;
+  ok !$fail, 'no error';
+  is_deeply $result, [1, 2], 'right structure';
+};
 
-# Stream inherited from previous subprocesses
-($fail, $result) = ();
-my @promises;
-my $me = $$;
-for (0 .. 1) {
-  push @promises, my $promise = Mojo::Promise->new;
-  my $subprocess = Mojo::IOLoop::Subprocess->new;
-  $subprocess->run(
-    sub { 1 + 1 },
+subtest 'No result' => sub {
+  my ($fail, $result);
+  Mojo::IOLoop::Subprocess->new->run(
+    sub {return},
     sub {
-      my ($subprocess, $err, $two) = @_;
-      $fail ||= $err;
-      push @$result, $two;
-      is $me, $$, 'we are the parent';
-      $promise->resolve;
+      my ($subprocess, $err, @results) = @_;
+      $fail   = $err;
+      $result = \@results;
     }
   );
-}
-Mojo::Promise->all(@promises)->wait;
-ok !$fail, 'no error';
-is_deeply $result, [2, 2], 'right structure';
+  Mojo::IOLoop->start;
+  ok !$fail, 'no error';
+  is_deeply $result, [], 'right structure';
+};
 
-# Exception
-$fail = undef;
-Mojo::IOLoop::Subprocess->new->run(
-  sub { die 'Whatever' },
-  sub {
-    my ($subprocess, $err) = @_;
-    $fail = $err;
+subtest 'Stream inherited from previous subprocesses' => sub {
+  my ($fail, $result);
+  my @promises;
+  my $me = $$;
+  for (0 .. 1) {
+    push @promises, my $promise = Mojo::Promise->new;
+    my $subprocess = Mojo::IOLoop::Subprocess->new;
+    $subprocess->run(
+      sub { 1 + 1 },
+      sub {
+        my ($subprocess, $err, $two) = @_;
+        $fail ||= $err;
+        push @$result, $two;
+        is $me, $$, 'we are the parent';
+        $promise->resolve;
+      }
+    );
   }
-);
-Mojo::IOLoop->start;
-like $fail, qr/Whatever/, 'right error';
+  Mojo::Promise->all(@promises)->wait;
+  ok !$fail, 'no error';
+  is_deeply $result, [2, 2], 'right structure';
+};
 
-# Non-zero exit status
-$fail       = undef;
-$subprocess = Mojo::IOLoop::Subprocess->new;
-$subprocess->run(
-  sub { exit 3 },
-  sub {
-    my ($subprocess, $err) = @_;
-    $fail = $err;
-  }
-);
-Mojo::IOLoop->start;
-is $subprocess->exit_code, 3, 'right exit code';
-like $fail, qr/offset 0/, 'right error';
+subtest 'Exception' => sub {
+  my $fail;
+  Mojo::IOLoop::Subprocess->new->run(
+    sub { die 'Whatever' },
+    sub {
+      my ($subprocess, $err) = @_;
+      $fail = $err;
+    }
+  );
+  Mojo::IOLoop->start;
+  like $fail, qr/Whatever/, 'right error';
+};
 
-# Serialization error
-$fail       = undef;
-$subprocess = Mojo::IOLoop::Subprocess->new;
-$subprocess->deserialize(sub { die 'Whatever' });
-$subprocess->run(
-  sub { 1 + 1 },
-  sub {
-    my ($subprocess, $err) = @_;
-    $fail = $err;
-  }
-);
-Mojo::IOLoop->start;
-like $fail, qr/Whatever/, 'right error';
+subtest 'Non-zero exit status' => sub {
+  my $fail;
+  my $subprocess = Mojo::IOLoop::Subprocess->new;
+  $subprocess->run(
+    sub { exit 3 },
+    sub {
+      my ($subprocess, $err) = @_;
+      $fail = $err;
+    }
+  );
+  Mojo::IOLoop->start;
+  is $subprocess->exit_code, 3, 'right exit code';
+  like $fail, qr/offset 0/, 'right error';
+};
 
-# Progress
-($fail, $result) = (undef, undef);
-my @progress;
-$subprocess = Mojo::IOLoop::Subprocess->new;
-$subprocess->run(
-  sub {
-    my $s = shift;
-    $s->progress(20);
-    $s->progress({percentage => 45});
-    $s->progress({percentage => 90}, {long_data => [1 .. 1e5]});
-    'yay';
-  },
-  sub {
-    my ($subprocess, $err, @res) = @_;
-    $fail   = $err;
-    $result = \@res;
-  }
-);
-$subprocess->on(
-  progress => sub {
-    my ($subprocess, @args) = @_;
-    push @progress, \@args;
-  }
-);
-Mojo::IOLoop->start;
-ok !$fail, 'no error';
-is_deeply $result, ['yay'], 'correct result';
-is_deeply \@progress, [[20], [{percentage => 45}], [{percentage => 90}, {long_data => [1 .. 1e5]}]], 'correct progress';
+subtest 'Serialization error' => sub {
+  my $fail;
+  my $subprocess = Mojo::IOLoop::Subprocess->new;
+  $subprocess->deserialize(sub { die 'Whatever' });
+  $subprocess->run(
+    sub { 1 + 1 },
+    sub {
+      my ($subprocess, $err) = @_;
+      $fail = $err;
+    }
+  );
+  Mojo::IOLoop->start;
+  like $fail, qr/Whatever/, 'right error';
+};
 
-# Cleanup
-($fail, $result) = ();
-my $file   = tempfile;
-my $called = 0;
-$subprocess = Mojo::IOLoop::Subprocess->new;
-$subprocess->on(cleanup => sub { $file->spurt(shift->serialize->({test => ++$called})) });
-$subprocess->run(
-  sub {'Hello Mojo!'},
-  sub {
-    my ($subprocess, $err, $hello) = @_;
-    $fail   = $err;
-    $result = $hello;
-  }
-);
-Mojo::IOLoop->start;
-is_deeply $subprocess->deserialize->($file->slurp), {test => 1}, 'cleanup event emitted once';
-ok !$fail, 'no error';
-is $result, 'Hello Mojo!', 'right result';
+subtest 'Progress' => sub {
+  my ($fail, $result);
+  my @progress;
+  my $subprocess = Mojo::IOLoop::Subprocess->new;
+  $subprocess->run(
+    sub {
+      my $s = shift;
+      $s->progress(20);
+      $s->progress({percentage => 45});
+      $s->progress({percentage => 90}, {long_data => [1 .. 1e5]});
+      'yay';
+    },
+    sub {
+      my ($subprocess, $err, @res) = @_;
+      $fail   = $err;
+      $result = \@res;
+    }
+  );
+  $subprocess->on(
+    progress => sub {
+      my ($subprocess, @args) = @_;
+      push @progress, \@args;
+    }
+  );
+  Mojo::IOLoop->start;
+  ok !$fail, 'no error';
+  is_deeply $result, ['yay'], 'correct result';
+  is_deeply \@progress, [[20], [{percentage => 45}], [{percentage => 90}, {long_data => [1 .. 1e5]}]],
+    'correct progress';
+};
+
+subtest 'Cleanup' => sub {
+  my ($fail, $result);
+  my $file       = tempfile;
+  my $called     = 0;
+  my $subprocess = Mojo::IOLoop::Subprocess->new;
+  $subprocess->on(cleanup => sub { $file->spurt(shift->serialize->({test => ++$called})) });
+  $subprocess->run(
+    sub {'Hello Mojo!'},
+    sub {
+      my ($subprocess, $err, $hello) = @_;
+      $fail   = $err;
+      $result = $hello;
+    }
+  );
+  Mojo::IOLoop->start;
+  is_deeply $subprocess->deserialize->($file->slurp), {test => 1}, 'cleanup event emitted once';
+  ok !$fail, 'no error';
+  is $result, 'Hello Mojo!', 'right result';
+};
 
 done_testing();