config_parser: Add support for checking file existence

This will be used to reduce the number of config parser errors printed
to the logs.

Change-Id: Ia0337da386bc5dbe32c04bf2c3264997a9ad6da1
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/test/test_config_parser.cpp b/test/test_config_parser.cpp
index 3bb0897..e742cdf 100644
--- a/test/test_config_parser.cpp
+++ b/test/test_config_parser.cpp
@@ -112,6 +112,7 @@
 
 TEST_F(TestConfigParser, EmptyObject)
 {
+    EXPECT_FALSE(parser.getFileExists());
     EXPECT_TRUE(parser.getFilename().empty());
     EXPECT_EQ(0, parser.getWarnings().size());
     EXPECT_EQ(SectionMap(), parser.map);
@@ -120,6 +121,7 @@
 TEST_F(TestConfigParser, ReadDirectory)
 {
     parser.setFile("/");
+    EXPECT_FALSE(parser.getFileExists());
     EXPECT_EQ("/", parser.getFilename());
     EXPECT_EQ(1, parser.getWarnings().size());
     EXPECT_EQ(SectionMap(), parser.map);
@@ -128,6 +130,7 @@
 TEST_F(TestConfigParser, ReadConfigDataMissingFile)
 {
     parser.setFile("/no-such-path");
+    EXPECT_FALSE(parser.getFileExists());
     EXPECT_EQ("/no-such-path", parser.getFilename());
     EXPECT_EQ(1, parser.getWarnings().size());
     EXPECT_EQ(SectionMap(), parser.map);
@@ -137,6 +140,7 @@
 {
     WriteSampleFile();
     parser.setFile(filename);
+    EXPECT_TRUE(parser.getFileExists());
     EXPECT_EQ(filename, parser.getFilename());
     EXPECT_EQ(4, parser.getWarnings().size());
     ValidateSectionMap();