dtoc: Add some tests for the fdt module

At present this module is tested via the dtoc tests. This is a bit painful
since the tests are at a higher level and so failures are more difficult
to diagnose.

Add some tests that exercise the fdt module directly.

Signed-off-by: Simon Glass <sjg@chromium.org>

3 files changed, 257 insertions, 2 deletions

diff --git a/tools/dtoc/fdt.py b/tools/dtoc/fdt.py
index d08b0b53e6..5cde8c125a 100644
--- a/tools/dtoc/fdt.py
+++ b/tools/dtoc/fdt.py
@@ -138,6 +138,7 @@ class Prop:
         else:
             return TYPE_INT, val
 
+    @classmethod
     def GetEmpty(self, type):
         """Get an empty / zero value of the given type
 
@@ -335,12 +336,19 @@ class Fdt:
         """
         return self._fdt
 
-    def CheckErr(errnum, msg):
+    def GetFdtObj(self):
+        """Get the contents of the FDT
+
+        Returns:
+            The FDT contents as a libfdt.Fdt object
+        """
+        return self._fdt_obj
+
+    def CheckErr(self, errnum, msg):
         if errnum:
             raise ValueError('Error %d: %s: %s' %
                 (errnum, libfdt.fdt_strerror(errnum), msg))
 
-
     def GetProps(self, node):
         """Get all properties from a node.
 
diff --git a/tools/dtoc/test_fdt b/tools/dtoc/test_fdt
new file mode 120000
index 0000000000..7c3b23031f
--- /dev/null
+++ b/tools/dtoc/test_fdt
@@ -0,0 +1 @@
+test_fdt.py
\ No newline at end of file
diff --git a/tools/dtoc/test_fdt.py b/tools/dtoc/test_fdt.py
new file mode 100755
index 0000000000..ba660ca9b7
--- /dev/null
+++ b/tools/dtoc/test_fdt.py
@@ -0,0 +1,246 @@
+#!/usr/bin/python
+# SPDX-License-Identifier: GPL-2.0+
+# Copyright (c) 2018 Google, Inc
+# Written by Simon Glass <sjg@chromium.org>
+#
+
+from optparse import OptionParser
+import glob
+import os
+import sys
+import unittest
+
+# Bring in the patman libraries
+our_path = os.path.dirname(os.path.realpath(__file__))
+for dirname in ['../patman', '..']:
+    sys.path.insert(0, os.path.join(our_path, dirname))
+
+import command
+import fdt
+from fdt import TYPE_BYTE, TYPE_INT, TYPE_STRING, TYPE_BOOL
+from fdt_util import fdt32_to_cpu
+import libfdt
+import test_util
+import tools
+
+class TestFdt(unittest.TestCase):
+    """Tests for the Fdt module
+
+    This includes unit tests for some functions and functional tests for the fdt
+    module.
+    """
+    @classmethod
+    def setUpClass(cls):
+        tools.PrepareOutputDir(None)
+
+    @classmethod
+    def tearDownClass(cls):
+        tools._FinaliseForTest()
+
+    def setUp(self):
+        self.dtb = fdt.FdtScan('tools/dtoc/dtoc_test_simple.dts')
+
+    def testFdt(self):
+        """Test that we can open an Fdt"""
+        self.dtb.Scan()
+        root = self.dtb.GetRoot()
+        self.assertTrue(isinstance(root, fdt.Node))
+
+    def testGetNode(self):
+        """Test the GetNode() method"""
+        node = self.dtb.GetNode('/spl-test')
+        self.assertTrue(isinstance(node, fdt.Node))
+        node = self.dtb.GetNode('/i2c@0/pmic@9')
+        self.assertTrue(isinstance(node, fdt.Node))
+        self.assertEqual('pmic@9', node.name)
+
+    def testFlush(self):
+        """Check that we can flush the device tree out to its file"""
+        fname = self.dtb._fname
+        with open(fname) as fd:
+            data = fd.read()
+        os.remove(fname)
+        with self.assertRaises(IOError):
+            open(fname)
+        self.dtb.Flush()
+        with open(fname) as fd:
+            data = fd.read()
+
+    def testPack(self):
+        """Test that packing a device tree works"""
+        self.dtb.Pack()
+
+    def testGetFdt(self):
+        """Tetst that we can access the raw device-tree data"""
+        self.assertTrue(isinstance(self.dtb.GetFdt(), bytearray))
+
+    def testGetProps(self):
+        """Tests obtaining a list of properties"""
+        node = self.dtb.GetNode('/spl-test')
+        props = self.dtb.GetProps(node)
+        self.assertEqual(['boolval', 'bytearray', 'byteval', 'compatible',
+                          'intarray', 'intval', 'longbytearray',
+                          'stringarray', 'stringval', 'u-boot,dm-pre-reloc'],
+                         sorted(props.keys()))
+
+    def testCheckError(self):
+        """Tests the ChecKError() function"""
+        with self.assertRaises(ValueError) as e:
+            self.dtb.CheckErr(-libfdt.NOTFOUND, 'hello')
+        self.assertIn('FDT_ERR_NOTFOUND: hello', str(e.exception))
+
+
+class TestNode(unittest.TestCase):
+    """Test operation of the Node class"""
+
+    @classmethod
+    def setUpClass(cls):
+        tools.PrepareOutputDir(None)
+
+    @classmethod
+    def tearDownClass(cls):
+        tools._FinaliseForTest()
+
+    def setUp(self):
+        self.dtb = fdt.FdtScan('tools/dtoc/dtoc_test_simple.dts')
+        self.node = self.dtb.GetNode('/spl-test')
+
+    def testOffset(self):
+        """Tests that we can obtain the offset of a node"""
+        self.assertTrue(self.node.Offset() > 0)
+
+    def testDelete(self):
+        """Tests that we can delete a property"""
+        node2 = self.dtb.GetNode('/spl-test2')
+        offset1 = node2.Offset()
+        self.node.DeleteProp('intval')
+        offset2 = node2.Offset()
+        self.assertTrue(offset2 < offset1)
+        self.node.DeleteProp('intarray')
+        offset3 = node2.Offset()
+        self.assertTrue(offset3 < offset2)
+
+    def testFindNode(self):
+        """Tests that we can find a node using the _FindNode() functoin"""
+        node = self.dtb.GetRoot()._FindNode('i2c@0')
+        self.assertEqual('i2c@0', node.name)
+        subnode = node._FindNode('pmic@9')
+        self.assertEqual('pmic@9', subnode.name)
+
+
+class TestProp(unittest.TestCase):
+    """Test operation of the Prop class"""
+
+    @classmethod
+    def setUpClass(cls):
+        tools.PrepareOutputDir(None)
+
+    @classmethod
+    def tearDownClass(cls):
+        tools._FinaliseForTest()
+
+    def setUp(self):
+        self.dtb = fdt.FdtScan('tools/dtoc/dtoc_test_simple.dts')
+        self.node = self.dtb.GetNode('/spl-test')
+        self.fdt = self.dtb.GetFdtObj()
+
+    def testGetEmpty(self):
+        """Tests the GetEmpty() function for the various supported types"""
+        self.assertEqual(True, fdt.Prop.GetEmpty(fdt.TYPE_BOOL))
+        self.assertEqual(chr(0), fdt.Prop.GetEmpty(fdt.TYPE_BYTE))
+        self.assertEqual(chr(0) * 4, fdt.Prop.GetEmpty(fdt.TYPE_INT))
+        self.assertEqual('', fdt.Prop.GetEmpty(fdt.TYPE_STRING))
+
+    def testGetOffset(self):
+        """Test we can get the offset of a property"""
+        prop = self.node.props['longbytearray']
+
+        # Add 12, which is sizeof(struct fdt_property), to get to start of data
+        offset = prop.GetOffset() + 12
+        data = self.dtb._fdt[offset:offset + len(prop.value)]
+        bytes = [chr(x) for x in data]
+        self.assertEqual(bytes, prop.value)
+
+    def testWiden(self):
+        """Test widening of values"""
+        node2 = self.dtb.GetNode('/spl-test2')
+        prop = self.node.props['intval']
+
+        # No action
+        prop2 = node2.props['intval']
+        prop.Widen(prop2)
+        self.assertEqual(fdt.TYPE_INT, prop.type)
+        self.assertEqual(1, fdt32_to_cpu(prop.value))
+
+        # Convert singla value to array
+        prop2 = self.node.props['intarray']
+        prop.Widen(prop2)
+        self.assertEqual(fdt.TYPE_INT, prop.type)
+        self.assertTrue(isinstance(prop.value, list))
+
+        # A 4-byte array looks like a single integer. When widened by a longer
+        # byte array, it should turn into an array.
+        prop = self.node.props['longbytearray']
+        prop2 = node2.props['longbytearray']
+        self.assertFalse(isinstance(prop2.value, list))
+        self.assertEqual(4, len(prop2.value))
+        prop2.Widen(prop)
+        self.assertTrue(isinstance(prop2.value, list))
+        self.assertEqual(9, len(prop2.value))
+
+        # Similarly for a string array
+        prop = self.node.props['stringval']
+        prop2 = node2.props['stringarray']
+        self.assertFalse(isinstance(prop.value, list))
+        self.assertEqual(7, len(prop.value))
+        prop.Widen(prop2)
+        self.assertTrue(isinstance(prop.value, list))
+        self.assertEqual(3, len(prop.value))
+
+        # Enlarging an existing array
+        prop = self.node.props['stringarray']
+        prop2 = node2.props['stringarray']
+        self.assertTrue(isinstance(prop.value, list))
+        self.assertEqual(2, len(prop.value))
+        prop.Widen(prop2)
+        self.assertTrue(isinstance(prop.value, list))
+        self.assertEqual(3, len(prop.value))
+
+
+def RunTests(args):
+    """Run all the test we have for the fdt model
+
+    Args:
+        args: List of positional args provided to fdt. This can hold a test
+            name to execute (as in 'fdt -t testFdt', for example)
+    """
+    result = unittest.TestResult()
+    sys.argv = [sys.argv[0]]
+    test_name = args and args[0] or None
+    for module in (TestFdt, TestNode, TestProp):
+        if test_name:
+            try:
+                suite = unittest.TestLoader().loadTestsFromName(test_name, module)
+            except AttributeError:
+                continue
+        else:
+            suite = unittest.TestLoader().loadTestsFromTestCase(module)
+        suite.run(result)
+
+    print result
+    for _, err in result.errors:
+        print err
+    for _, err in result.failures:
+        print err
+
+if __name__ != '__main__':
+    sys.exit(1)
+
+parser = OptionParser()
+parser.add_option('-t', '--test', action='store_true', dest='test',
+                  default=False, help='run tests')
+(options, args) = parser.parse_args()
+
+# Run our meagre tests
+if options.test:
+    RunTests(args)