test_sdk_exists to be based on apksigner, that's the requirement

Before, lots of pieces of the Android SDK were required for fdroidserver to
operate, like aapt, zipalign, etc.  Now, apksigner is the only requirement.

%"support APK Signature v2+"
!889

fdroidserver/common.py

@@ -728,13 +728,16 @@ def test_aapt_version(aapt):
 
 def test_sdk_exists(thisconfig):
     if 'sdk_path' not in thisconfig:
-        # TODO convert this to apksigner once it is required
-        if 'aapt' in thisconfig and os.path.isfile(thisconfig['aapt']):
-            test_aapt_version(thisconfig['aapt'])
-            return True
-        else:
-            logging.error(_("'sdk_path' not set in config.yml!"))
-            return False
+        # check the 'apksigner' value in the config to see if its new enough
+        f = thisconfig.get('apksigner', '')
+        if os.path.isfile(f):
+            sdk_path = os.path.dirname(os.path.dirname(os.path.dirname(f)))
+            tmpconfig = {'sdk_path': sdk_path}
+            find_apksigner(tmpconfig)
+            if os.path.exists(tmpconfig.get('apksigner', '')):
+                return True
+        logging.error(_("'sdk_path' not set in config.yml!"))
+        return False
     if thisconfig['sdk_path'] == default_config['sdk_path']:
         logging.error(_('No Android SDK found!'))
         logging.error(_('You can use ANDROID_HOME to set the path to your SDK, i.e.:'))
@@ -748,6 +751,9 @@ def test_sdk_exists(thisconfig):
         logging.critical(_("Android SDK path '{path}' is not a directory!")
                          .format(path=thisconfig['sdk_path']))
         return False
+    find_apksigner(thisconfig)
+    if not os.path.exists(thisconfig.get('apksigner', '')):
+        return False
     return True
 
 

tests/common.TestCase

@@ -2051,6 +2051,75 @@ class CommonTest(unittest.TestCase):
         config = fdroidserver.common.read_config(fdroidserver.common.options)
         self.assertEqual('/usr/lib/jvm/java-8-openjdk', config.get('java_paths', {}).get('8'))
 
+    @mock.patch.dict(os.environ, {'PATH': os.getenv('PATH')}, clear=True)
+    def test_test_sdk_exists_fails_on_bad_sdk_path(self):
+        config = {'sdk_path': 'nothinghere'}
+        self.assertFalse(fdroidserver.common.test_sdk_exists(config))
+
+    @mock.patch.dict(os.environ, {'PATH': os.getenv('PATH')}, clear=True)
+    def test_test_sdk_exists_fails_on_empty(self):
+        self.assertFalse(fdroidserver.common.test_sdk_exists(dict()))
+
+    @mock.patch.dict(os.environ, {'PATH': os.getenv('PATH')}, clear=True)
+    def test_test_sdk_exists_fails_on_non_existent(self):
+        config = {'sdk_path': os.path.join(self.testdir, 'non_existent')}
+        self.assertFalse(fdroidserver.common.test_sdk_exists(config))
+
+    @mock.patch.dict(os.environ, {'PATH': os.getenv('PATH')}, clear=True)
+    def test_test_sdk_exists_fails_on_file(self):
+        f = os.path.join(self.testdir, 'testfile')
+        open(f, 'w').close()
+        config = {'sdk_path': f}
+        self.assertFalse(fdroidserver.common.test_sdk_exists(config))
+
+    @mock.patch.dict(os.environ, {'PATH': '/nonexistent'}, clear=True)
+    def test_test_sdk_exists_valid_apksigner_in_config(self):
+        apksigner = os.path.join(
+            self.testdir,
+            'build-tools',
+            fdroidserver.common.MINIMUM_APKSIGNER_BUILD_TOOLS_VERSION,
+            'apksigner',
+        )
+        os.makedirs(os.path.dirname(apksigner))
+        with open(apksigner, 'w') as fp:
+            fp.write('#!/bin/sh\ndate\n')
+        os.chmod(apksigner, 0o0755)
+        config = {'apksigner': apksigner}
+        self.assertTrue(fdroidserver.common.test_sdk_exists(config))
+
+    @mock.patch.dict(os.environ, {'PATH': '/nonexistent'}, clear=True)
+    def test_test_sdk_exists_old_apksigner_in_config(self):
+        apksigner = os.path.join(self.testdir, 'build-tools', '28.0.0', 'apksigner')
+        os.makedirs(os.path.dirname(apksigner))
+        with open(apksigner, 'w') as fp:
+            fp.write('#!/bin/sh\ndate\n')
+        os.chmod(apksigner, 0o0755)
+        config = {'apksigner': apksigner}
+        self.assertFalse(fdroidserver.common.test_sdk_exists(config))
+
+    @mock.patch.dict(os.environ, {'PATH': '/nonexistent'}, clear=True)
+    def test_test_sdk_exists_with_valid_apksigner(self):
+        apksigner = (
+            Path(self.testdir)
+            / 'build-tools'
+            / fdroidserver.common.MINIMUM_APKSIGNER_BUILD_TOOLS_VERSION
+            / 'apksigner'
+        )
+        apksigner.parent.mkdir(parents=True)
+        apksigner.write_text('#!/bin/sh\ndate\n')
+        apksigner.chmod(0o0755)
+        config = {'sdk_path': self.testdir}
+        self.assertTrue(fdroidserver.common.test_sdk_exists(config))
+
+    @mock.patch.dict(os.environ, {'PATH': '/nonexistent'}, clear=True)
+    def test_test_sdk_exists_with_old_apksigner(self):
+        apksigner = Path(self.testdir) / 'build-tools' / '17.0.0' / 'apksigner'
+        apksigner.parent.mkdir(parents=True)
+        apksigner.write_text('#!/bin/sh\ndate\n')
+        apksigner.chmod(0o0755)
+        config = {'sdk_path': self.testdir}
+        self.assertFalse(fdroidserver.common.test_sdk_exists(config))
+
     def test_loading_config_buildserver_yml(self):
         """Smoke check to make sure this file is properly parsed"""
         os.chdir(self.tmpdir)