diff --git a/src/rosdep2/platforms/debian.py b/src/rosdep2/platforms/debian.py
index 8bb78c5b2..404b6d84f 100644
--- a/src/rosdep2/platforms/debian.py
+++ b/src/rosdep2/platforms/debian.py
@@ -294,13 +294,11 @@ def get_version_strings(self):
         return ['apt-get {}'.format(version)]
 
     def _get_install_commands_for_package(self, base_cmd, package_or_list):
-        def pkg_command(p):
-            return self.elevate_priv(base_cmd + [p])
-
-        if isinstance(package_or_list, list):
-            return [pkg_command(p) for p in package_or_list]
+        if isinstance(package_or_list, str):
+            return self.elevate_priv(base_cmd + [package_or_list])
         else:
-            return pkg_command(package_or_list)
+            # sort to make the output deterministic
+            return self.elevate_priv(base_cmd + sorted(package_or_list))
 
     def get_install_command(self, resolved, interactive=True, reinstall=False, quiet=False):
         packages = self.get_packages_to_install(resolved, reinstall=reinstall)
@@ -312,4 +310,9 @@ def get_install_command(self, resolved, interactive=True, reinstall=False, quiet
         if quiet:
             base_cmd.append('-qq')
 
-        return [self._get_install_commands_for_package(base_cmd, p) for p in _iterate_packages(packages, reinstall)]
+        return [
+            self._get_install_commands_for_package(
+                base_cmd,
+                _iterate_packages(packages, reinstall),
+            )
+        ]
diff --git a/test/test_rosdep_debian.py b/test/test_rosdep_debian.py
index 428b301f4..bba212927 100644
--- a/test/test_rosdep_debian.py
+++ b/test/test_rosdep_debian.py
@@ -126,13 +126,11 @@ def test(expected_prefix, mock_get_packages_to_install, mock_read_stdout):
         assert [] == installer.get_install_command(['fake'])
 
         mock_get_packages_to_install.return_value = ['a', 'b']
-        expected = [expected_prefix + ['apt-get', 'install', '-y', 'a'],
-                    expected_prefix + ['apt-get', 'install', '-y', 'b']]
+        expected = [expected_prefix + ['apt-get', 'install', '-y', 'a', 'b']]
         val = installer.get_install_command(['whatever'], interactive=False)
         print('VAL', val)
         assert val == expected, val
-        expected = [expected_prefix + ['apt-get', 'install', 'a'],
-                    expected_prefix + ['apt-get', 'install', 'b']]
+        expected = [expected_prefix + ['apt-get', 'install', 'a', 'b']]
         val = installer.get_install_command(['whatever'], interactive=True)
         assert val == expected, val
     try:
diff --git a/test/test_rosdep_installers.py b/test/test_rosdep_installers.py
index 4b91a3f22..e7609b290 100644
--- a/test/test_rosdep_installers.py
+++ b/test/test_rosdep_installers.py
@@ -617,7 +617,6 @@ def test_RosdepInstaller_install_resolved(mock_geteuid):
                 raise
             return True
     stdout_lines = [x.strip() for x in stdout.getvalue().split('\n') if x.strip()]
-    assert len(stdout_lines) == 3
+    assert len(stdout_lines) == 2
     assert stdout_lines[0] == '#[apt] Installation commands:'
-    assert 'sudo -H apt-get install rosdep-fake1' in stdout_lines, 'stdout_lines: %s' % stdout_lines
-    assert 'sudo -H apt-get install rosdep-fake2' in stdout_lines, 'stdout_lines: %s' % stdout_lines
+    assert 'sudo -H apt-get install rosdep-fake1 rosdep-fake2' in stdout_lines, 'stdout_lines: %s' % stdout_lines
diff --git a/test/test_rosdep_main.py b/test/test_rosdep_main.py
index c94143c24..d24759722 100644
--- a/test/test_rosdep_main.py
+++ b/test/test_rosdep_main.py
@@ -199,15 +199,11 @@ def read_stdout(cmd, capture_stderr=False):
                     '--from-paths', catkin_tree
                 ] + cmd_extras)
                 stdout, stderr = b
+                # the output is sorted in ascending order
                 expected = [
                     '#[apt] Installation commands:',
-                    '  sudo -H apt-get install ros-fuerte-catkin',
-                    '  sudo -H apt-get install libboost1.40-all-dev',
-                    '  sudo -H apt-get install libeigen3-dev',
-                    '  sudo -H apt-get install libtinyxml-dev',
-                    '  sudo -H apt-get install libltdl-dev',
-                    '  sudo -H apt-get install libtool',
-                    '  sudo -H apt-get install libcurl4-openssl-dev',
+                    '  sudo -H apt-get install libboost1.40-all-dev libcurl4-openssl-dev'
+                    ' libeigen3-dev libltdl-dev libtinyxml-dev libtool ros-fuerte-catkin',
                 ]
                 lines = stdout.getvalue().splitlines()
                 assert set(lines) == set(expected), lines