Add ext2 reading tests: usage, label and UUID (!49)

The file system reading methods report errors into Partition messages
because they are used as part of the GParted refresh, rather than
reporting errors into OperationDetails used when applying operations.
Therefore test for no messages for success and print the messages on
failure.

For example, temporarily breaking the read label test code by setting
the wrong file system image name produces this:

    $ ./test_ext2 --gtest_filter='ext2Test.CreateAndReadLabel'
    Running main() from test_ext2.cc
    Note: Google Test filter = ext2Test.CreateAndReadLabel
    [==========] Running 1 test from 1 test case.
    [----------] Global test environment set-up.
    [----------] 1 test from ext2Test
    [ RUN      ] ext2Test.CreateAndReadLabel
    test_ext2.cc:311: Failure
    Value of: m_partition.get_messages().empty()
      Actual: false
    Expected: true
    Partition messages:
    e2label: No such file or directory while trying to open /does_not_exist/test_ext2.img
    Couldn't find valid filesystem superblock.

    [  FAILED  ] ext2Test.CreateAndReadLabel (77 ms)
    [----------] 1 test from ext2Test (77 ms total)

    [----------] Global test environment tear-down
    [==========] 1 test from 1 test case ran. (85 ms total)
    [  PASSED  ] 0 tests.
    [  FAILED  ] 1 test, listed below:
    [  FAILED  ] ext2Test.CreateAndReadLabel

     1 FAILED TEST
    $ echo $?
    1

Closes !49 - Add file system interface tests

tests/test_ext2.cc

@@ -43,6 +43,7 @@
 
 #include <iostream>
 #include <fstream>
+#include <vector>
 #include <stdlib.h>
 #include <stddef.h>
 #include <stdio.h>
@@ -115,6 +116,17 @@ Glib::ustring strip_markup(const Glib::ustring& str)
 }
 
 
+// Print method for the messages in a Partition object.
+std::ostream& operator<<(std::ostream& out, const Partition& partition)
+{
+	const std::vector<Glib::ustring> messages = partition.get_messages();
+	out << "Partition messages:\n";
+	for (unsigned int i = 0; i < messages.size(); i++)
+		out << messages[i];
+	return out;
+}
+
+
 // Print method for OperationDetailStatus.
 std::ostream& operator<<(std::ostream& out, const OperationDetailStatus od_status)
 {
@@ -157,12 +169,12 @@ std::ostream& operator<<(std::ostream& out, const OperationDetail& od)
 //     Skipping tests at runtime with GTEST_SKIP() #1544
 //     https://github.com/google/googletest/pull/1544
 //     (Merged after Google Test 1.8.1)
-#define SKIP_IF_FS_DOESNT_SUPPORT(opt)                                           \
-	if (s_ext2_support.opt != FS::EXTERNAL)                                  \
-	{                                                                        \
-		std::cout << __FILE__ << ":" << __LINE__ << ": Skip test.  "     \
-		          << "Not supported or support not found" << std::endl;  \
-		return;                                                          \
+#define SKIP_IF_FS_DOESNT_SUPPORT(opt)                                                    \
+	if (s_ext2_support.opt != FS::EXTERNAL)                                           \
+	{                                                                                 \
+		std::cout << __FILE__ << ":" << __LINE__ << ": Skip test.  "              \
+		          << #opt << " not supported or support not found" << std::endl;  \
+		return;                                                                   \
 	}
 
 
@@ -254,6 +266,68 @@ TEST_F(ext2Test, Create)
 }
 
 
+TEST_F(ext2Test, CreateAndReadUsage)
+{
+	SKIP_IF_FS_DOESNT_SUPPORT(create);
+	SKIP_IF_FS_DOESNT_SUPPORT(read);
+
+	extra_setup();
+	ASSERT_TRUE(s_ext2_obj->create(m_partition, m_operation_detail)) << m_operation_detail;
+
+	s_ext2_obj->set_used_sectors(m_partition);
+	// Test file system usage is reported correctly.
+	// Used is between 0 and length.
+	EXPECT_LE(0, m_partition.sectors_used);
+	EXPECT_LE(m_partition.sectors_used, m_partition.get_sector_length());
+	// Unused is between 0 and length.
+	EXPECT_LE(0, m_partition.sectors_unused);
+	EXPECT_LE(m_partition.sectors_unused, m_partition.get_sector_length());
+	// Unallocated is 0.
+	EXPECT_EQ(m_partition.sectors_unallocated, 0);
+	// Used + unused = length.
+	EXPECT_EQ(m_partition.sectors_used + m_partition.sectors_unused, m_partition.get_sector_length());
+
+	// Test messages from read operation are empty or print them.
+	EXPECT_TRUE(m_partition.get_messages().empty()) << m_partition;
+}
+
+
+TEST_F(ext2Test, CreateAndReadLabel)
+{
+	SKIP_IF_FS_DOESNT_SUPPORT(create);
+	SKIP_IF_FS_DOESNT_SUPPORT(read_label);
+
+	const char* fs_label = "TEST_LABEL";
+	extra_setup();
+	m_partition.set_filesystem_label(fs_label);
+	ASSERT_TRUE(s_ext2_obj->create(m_partition, m_operation_detail)) << m_operation_detail;
+
+	// Test reading the label is successful.
+	s_ext2_obj->read_label(m_partition);
+	EXPECT_STREQ(fs_label, m_partition.get_filesystem_label().c_str());
+
+	// Test messages from read operation are empty or print them.
+	EXPECT_TRUE(m_partition.get_messages().empty()) << m_partition;
+}
+
+
+TEST_F(ext2Test, CreateAndReadUUID)
+{
+	SKIP_IF_FS_DOESNT_SUPPORT(create);
+	SKIP_IF_FS_DOESNT_SUPPORT(read_uuid);
+
+	extra_setup();
+	ASSERT_TRUE(s_ext2_obj->create(m_partition, m_operation_detail)) << m_operation_detail;
+
+	// Test reading the UUID is successful.
+	s_ext2_obj->read_uuid(m_partition);
+	EXPECT_EQ(m_partition.uuid.size(), 36U);
+
+	// Test messages from read operation are empty or print them.
+	EXPECT_TRUE(m_partition.get_messages().empty()) << m_partition;
+}
+
+
 }  // namespace GParted