binman: Simplify the entry test

The current test for the 'entry' module is a bit convoluted since it has
to import the module multiple times. It also relies on ordering, in that
test1EntryNoImportLib() must run before test2EntryImportLib() if they are
running in the same Python process.

This is unreliable since neither the ordering of tests nor the process
that they run in is defined.

Fix this by always reloading the entry in these two tests. Also add a
check that the expected value of have_importlib is obtained.

This corrects a code-coverage problem in the 'entry' module on some
systems.

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

tools/binman/entry_test.py

@@ -9,12 +9,11 @@ import os
 import sys
 import unittest
 
+import entry
 import fdt
 import fdt_util
 import tools
 
-entry = None
-
 class TestEntry(unittest.TestCase):
     def setUp(self):
         tools.PrepareOutputDir(None)
@@ -29,16 +28,7 @@ class TestEntry(unittest.TestCase):
         dtb = fdt.FdtScan(fname)
         return dtb.GetNode('/binman/u-boot')
 
-    def test1EntryNoImportLib(self):
+    def _ReloadEntry(self):
-        """Test that we can import Entry subclassess successfully"""
-
-        sys.modules['importlib'] = None
-        global entry
-        import entry
-        entry.Entry.Create(None, self.GetNode(), 'u-boot')
-
-    def test2EntryImportLib(self):
-        del sys.modules['importlib']
         global entry
         if entry:
             if sys.version_info[0] >= 3:
@@ -48,8 +38,21 @@ class TestEntry(unittest.TestCase):
                 reload(entry)
         else:
             import entry
+
+    def test1EntryNoImportLib(self):
+        """Test that we can import Entry subclassess successfully"""
+        sys.modules['importlib'] = None
+        global entry
+        self._ReloadEntry()
+        entry.Entry.Create(None, self.GetNode(), 'u-boot')
+        self.assertFalse(entry.have_importlib)
+
+    def test2EntryImportLib(self):
+        del sys.modules['importlib']
+        global entry
+        self._ReloadEntry()
         entry.Entry.Create(None, self.GetNode(), 'u-boot-spl')
-        del entry
+        self.assertTrue(entry.have_importlib)
 
     def testEntryContents(self):
         """Test the Entry bass class"""
@@ -59,7 +62,6 @@ class TestEntry(unittest.TestCase):
 
     def testUnknownEntry(self):
         """Test that unknown entry types are detected"""
-        import entry
         Node = collections.namedtuple('Node', ['name', 'path'])
         node = Node('invalid-name', 'invalid-path')
         with self.assertRaises(ValueError) as e:
@@ -69,7 +71,6 @@ class TestEntry(unittest.TestCase):
 
     def testUniqueName(self):
         """Test Entry.GetUniqueName"""
-        import entry
         Node = collections.namedtuple('Node', ['name', 'parent'])
         base_node = Node('root', None)
         base_entry = entry.Entry(None, None, base_node, read_node=False)
@@ -80,7 +81,6 @@ class TestEntry(unittest.TestCase):
 
     def testGetDefaultFilename(self):
         """Trivial test for this base class function"""
-        import entry
         base_entry = entry.Entry(None, None, None, read_node=False)
         self.assertIsNone(base_entry.GetDefaultFilename())