How to use the sos.targets.file_target function in sos

[A_3]
input: 'a1.md', 'a2.md'
output: 'out.md'
report:     input=['a1.md', 'a2.md'], output='out.md'
''')
        wf = script.workflow()
        Base_Executor(wf).run()
        with open('a1.md') as a:
            self.assertEqual(a.read(), 'a1\n\n')
        with open('a2.md') as a:
            self.assertEqual(a.read(), 'a2\n\n')
        with open('out.md') as a:
            self.assertEqual(a.read(), 'a1\n\na2\n\n')
        for name in ('a1.md', 'a2.md', 'out.md'):
            if file_target(name).exists():
                file_target(name).unlink()
        wf = script.workflow()
        Base_Executor(wf).run()

"C1 (C1.txt)";
"B1 (B1.txt)";
"B2 (B2.txt)";
"C3 (C3.txt)";
"B3 (B3.txt)" -> "B2 (B2.txt)";
"C4 (C4.txt)" -> "C3 (C3.txt)";
"C4 (C4.txt)" -> "C2 (C2.txt)";
"C2 (C2.txt)" -> "C1 (C1.txt)";
"C1 (C1.txt)" -> "B2 (B2.txt)";
"B2 (B2.txt)" -> "B1 (B1.txt)";
"C3 (C3.txt)" -> "C1 (C1.txt)";
}
''')
        Base_Executor(wf).run(targets=['B1.txt'])
        for f in ['A1.txt', 'A2.txt']:
            self.assertFalse(file_target(f).target_exists())
        for f in [
                'C2.txt', 'B2.txt', 'B1.txt', 'B3.txt', 'C1.txt', 'C3.txt',
                'C4.txt'
        ]:
            t = file_target(f)
            self.assertTrue(t.target_exists())
            t.unlink()
        #
        # test 2, we would like to generate two files
        dag = Base_Executor(wf).initialize_dag(targets=['B2.txt', 'C2.txt'])
        # note that A2 is no longer mentioned
        self.assertDAG(
            dag, '''
strict digraph "" {
"C4 (C4.txt)";
"B2 (B2.txt)";

cp local.txt result_remote.txt
  echo 'adf' >> 'result_remote.txt'

''')
        self.assertEqual(
            subprocess.call(
                'sos run test_remote.sos -c ~/docker.yml -r docker -s force -q localhost',
                shell=True), 0)
        self.assertFalse(file_target('result_remote.txt').target_exists())
        #self.assertEqual(subprocess.call('sos preview result_remote.txt -c ~/docker.yml -r docker', shell=True), 0)
        #self.assertNotEqual(subprocess.call('sos preview result_remote.txt', shell=True), 0)
        self.assertEqual(
            subprocess.call(
                'sos remote pull docker --files result_remote.txt -c ~/docker.yml',
                shell=True), 0)
        self.assertTrue(file_target('result_remote.txt').target_exists())
        #self.assertEqual(subprocess.call('sos preview result_remote.txt', shell=True), 0)
        with open('result_remote.txt') as w:
            content = w.read()
            self.assertTrue('something' in content, 'Got {}'.format(content))
            self.assertTrue('adf' in content, 'Got {}'.format(content))
        # test sos remote run
        self.assertEqual(
            subprocess.call(
                'sos remote run docker -c  ~/docker.yml --cmd cp result_remote.txt result_remote1.txt ',
                shell=True), 0)
        self.assertEqual(
            subprocess.call(
                'sos remote pull docker --files result_remote1.txt -c ~/docker.yml',
                shell=True), 0)
        self.assertTrue(file_target('result_remote1.txt').target_exists())

report: output='default_10.md'
A_10

[20]
report: output='default_20.md'
A_20

[100]
# generate report
Rmarkdown(input=['default_10.md', 'default_20.md'], output='output.html')
''')
        wf = script.workflow()
        Base_Executor(wf, config={'report_output': '${step_name}.md'}).run()
        for f in ['default_10.md', 'default_20.md', 'output.html']:
            self.assertTrue(file_target(f).exists())
            file_target(f).unlink()

def testZap(self):
        '''Test zap'''
        with open('testzap.txt', 'w') as sf:
            sf.write('some text')
        path('testzap.txt').zap()
        self.assertTrue(os.path.isfile('testzap.txt.zapped'))
        self.assertFalse(os.path.isfile('testzap.txt'))
        # re-zap is ok
        file_target('testzap.txt').zap()
        self.assertTrue(os.path.isfile('testzap.txt.zapped'))
        self.assertFalse(os.path.isfile('testzap.txt'))
        # non-existent file
        os.remove('testzap.txt.zapped')
        self.assertRaises(FileNotFoundError, path('testzap.txt').zap)
        #
        with open('testzap.txt', 'w') as sf:
            sf.write('some text')
        with open('testzap1.txt', 'w') as sf:
            sf.write('some text')
        paths('testzap.txt', 'testzap1.txt').zap()
        self.assertTrue(os.path.isfile('testzap.txt.zapped'))
        self.assertFalse(os.path.isfile('testzap.txt'))
        self.assertTrue(os.path.isfile('testzap1.txt.zapped'))
        self.assertFalse(os.path.isfile('testzap1.txt'))
        #

def testOutputGroupWith(self):
        '''Test option group_with in output statement'''
        self.touch(['a.txt', 'b.txt'])
        for ofile in ['a.txt1', 'b.txt2']:
            if file_target(ofile).exists():
                file_target(ofile).unlink()
        #
        # string input
        script = SoS_Script(r'''
[0]
files = ['a.txt', 'b.txt']
vars = [1, 2]

input: files, group_by=1
output: f"{_input}.bak", group_with=dict(_vars=vars[_index])
run: expand=True
    touch {_output}

[1]
assert(_vars == _index + 1)
''')

def tearDown(self):
        for f in self.temp_files:
            file_target(f).unlink()
        os.chdir(self.olddir)

def testOptionWorkdir(self):
        '''Test option workdir of tasks'''
        if not os.path.isdir('temp_wdr'):
            os.mkdir('temp_wdr')
        with open(os.path.join('temp_wdr', 'a.txt'), 'w') as tmp:
            tmp.write('hello')
        script = SoS_Script(r'''
[A_1]
run: workdir='temp_wdr'
  cp -f a.txt a2.txt
''')
        wf = script.workflow()
        Base_Executor(wf).run()
        self.assertTrue(
            file_target(os.path.join('temp_wdr', 'a2.txt')).target_exists())
        with open(os.path.join('temp_wdr', 'a.txt')) as tmp:
            self.assertEqual('hello', tmp.read())

"C4 (C4.txt)" -> "C3 (C3.txt)";
"C4 (C4.txt)" -> "C2 (C2.txt)";
"C2 (C2.txt)" -> "C1 (C1.txt)";
"C1 (C1.txt)" -> "B2 (B2.txt)";
"B2 (B2.txt)" -> "B1 (B1.txt)";
"C3 (C3.txt)" -> "C1 (C1.txt)";
}
''')
        Base_Executor(wf).run(targets=['B1.txt'])
        for f in ['A1.txt', 'A2.txt']:
            self.assertFalse(file_target(f).target_exists())
        for f in [
                'C2.txt', 'B2.txt', 'B1.txt', 'B3.txt', 'C1.txt', 'C3.txt',
                'C4.txt'
        ]:
            t = file_target(f)
            self.assertTrue(t.target_exists())
            t.unlink()
        #
        # test 2, we would like to generate two files
        dag = Base_Executor(wf).initialize_dag(targets=['B2.txt', 'C2.txt'])
        # note that A2 is no longer mentioned
        self.assertDAG(
            dag, '''
strict digraph "" {
"C4 (C4.txt)";
"B2 (B2.txt)";
"C3 (C3.txt)";
"B3 (B3.txt)";
"C2 (C2.txt)";
"C1 (C1.txt)";
"C4 (C4.txt)" -> "C2 (C2.txt)";

def tearDown(self):
        for f in self.temp_files:
            file_target(f).unlink()
        os.chdir(self.olddir)