diff --git a/src/main_test.cpp b/src/main_test.cpp
index 6c8cf42..55ff174 100644
--- a/src/main_test.cpp
+++ b/src/main_test.cpp
@@ -291,9 +291,8 @@ TEST(IntelHexTest, PaddingWidth)
 
 TEST(IntelHexTest, ParseLine)
 {
-  auto input = ":1000000000200020C5020008B9020008BB02000859";
   Line line{};
-  auto b = IntelHex::parseLine(input, line);
+  auto b = IntelHex::parseLine(":1000000000200020C5020008B9020008BB02000859", line);
   EXPECT_EQ(1, b);
   EXPECT_EQ(1, line.length == 0x10);
   EXPECT_EQ(1, line.address == 0);
@@ -302,6 +301,41 @@ TEST(IntelHexTest, ParseLine)
   EXPECT_EQ(1, line.checksum == 89);
 }
 
+TEST(IntelHexTest, ParseLineError1)
+{
+  Line line{};
+  auto b = IntelHex::parseLine(":10000000", line);
+  EXPECT_EQ(0, b);
+}
+
+TEST(IntelHexTest, ParseLineError2)
+{
+  Line line{};
+  auto b = IntelHex::parseLine("0000000000", line);
+  EXPECT_EQ(0, b);
+}
+
+TEST(IntelHexTest, ParseLineError3)
+{
+  Line line{};
+  auto b = IntelHex::parseLine(":0000000000", line);
+  EXPECT_EQ(0, b);
+}
+
+TEST(IntelHexTest, ParseLineError4)
+{
+  Line line{};
+  auto b = IntelHex::parseLine(":00000000F6", line);
+  EXPECT_EQ(0, b);
+}
+
+TEST(IntelHexTest, ParseLineError5)
+{
+  Line line{};
+  auto b = IntelHex::parseLine(":1000000000200020C5020008B9020008BB02000800", line);
+  EXPECT_EQ(0, b);
+}
+
 TEST(IntelHexTest, ConvertLine)
 {
   Line line{};