Add more unit tests

pkg/commands/patch/patch_modifier_test.go

@@ -223,6 +223,24 @@ func TestModifyPatchForRange(t *testing.T) {
 -last line
 \ No newline at end of file
 +last line
+`,
+		},
+		{
+			testName:       "add newline to end of file, reversed",
+			filename:       "filename",
+			firstLineIndex: -100,
+			lastLineIndex:  100,
+			reverse:        true,
+			diffText:       addNewlineToEndOfFile,
+			expected: `--- a/filename
++++ b/filename
+@@ -60,4 +60,4 @@ grape
+ ...
+ ...
+ ...
+-last line
+\ No newline at end of file
++last line
 `,
 		},
 		{
@@ -240,6 +258,24 @@ func TestModifyPatchForRange(t *testing.T) {
 -last line
 +last line
 \ No newline at end of file
+`,
+		},
+		{
+			testName:       "remove newline from end of file, reversed",
+			filename:       "filename",
+			firstLineIndex: -100,
+			lastLineIndex:  100,
+			reverse:        true,
+			diffText:       removeNewlinefromEndOfFile,
+			expected: `--- a/filename
++++ b/filename
+@@ -60,4 +60,4 @@ grape
+ ...
+ ...
+ ...
+-last line
++last line
+\ No newline at end of file
 `,
 		},
 		{
@@ -255,6 +291,24 @@ func TestModifyPatchForRange(t *testing.T) {
  ...
  ...
 -last line
+`,
+		},
+		{
+			testName:       "remove newline from end of file, removal only, reversed",
+			filename:       "filename",
+			firstLineIndex: 8,
+			lastLineIndex:  8,
+			reverse:        true,
+			diffText:       removeNewlinefromEndOfFile,
+			expected: `--- a/filename
++++ b/filename
+@@ -60,5 +60,4 @@ grape
+ ...
+ ...
+ ...
+-last line
+ last line
+\ No newline at end of file
 `,
 		},
 		{
@@ -272,6 +326,23 @@ func TestModifyPatchForRange(t *testing.T) {
  last line
 +last line
 \ No newline at end of file
+`,
+		},
+		{
+			testName:       "remove newline from end of file, addition only, reversed",
+			filename:       "filename",
+			firstLineIndex: 9,
+			lastLineIndex:  9,
+			reverse:        true,
+			diffText:       removeNewlinefromEndOfFile,
+			expected: `--- a/filename
++++ b/filename
+@@ -60,3 +60,4 @@ grape
+ ...
+ ...
+ ...
++last line
+\ No newline at end of file
 `,
 		},
 		{
@@ -363,6 +434,20 @@ func TestModifyPatchForRange(t *testing.T) {
 @@ -0,0 +1,1 @@
 +new line
 \ No newline at end of file
+`,
+		},
+		{
+			testName:       "adding a new line to a previously empty file, reversed",
+			filename:       "newfile",
+			firstLineIndex: -100,
+			lastLineIndex:  100,
+			diffText:       addNewlineToPreviouslyEmptyFile,
+			reverse:        true,
+			expected: `--- a/newfile
++++ b/newfile
+@@ -0,0 +1,1 @@
++new line
+\ No newline at end of file
 `,
 		},
 		{