fix incorrect newline handling

assets/multiline/expected-dyff-spruce.human

@@ -13,18 +13,27 @@
 
 
 files.newline.content
-  ± value change in multiline text (three inserts, three deletions)
+  ± value change in multiline text (four inserts, four deletions)
       
+    - 
     - This line will change 1
     + This line changed 1
       UnChanged line
+      
     - This line will change 2
     + This line changed 2
+      UnChanged line
+      
+      
+    - 
+      Moved line
+    + 
       
       
       UnChanged line
     - This line will change 3
     + This line changed 3
+    + 
       
       
 
@@ -81,8 +90,8 @@
       [22 lines unchanged)]
       
       End line 1
-      End line 1
-      End line 1
-      End line 1
+      End line 2
+      End line 3
+      End line 4
 
 

assets/multiline/from.yml

@@ -15,14 +15,18 @@ files:
     
     This line will change 1
     UnChanged line
-
+    
     This line will change 2
-
-
     UnChanged line
-    This line will change 3
     
     
+    
+    Moved line
+    
+    
+    UnChanged line
+    This line will change 3
+    
 
 - name: complex
   content: |
@@ -91,6 +95,6 @@ files:
     Truncated line
     Truncated line
     End line 1
-    End line 1
-    End line 1
-    End line 1
+    End line 2
+    End line 3
+    End line 4

assets/multiline/to.yml

@@ -12,13 +12,17 @@ files:
   # + to keep trailing newlines
   content: |+
     
-    
     This line changed 1
     UnChanged line
-
+    
     This line changed 2
-
-
+    UnChanged line
+    
+    
+    Moved line
+    
+    
+    
     UnChanged line
     This line changed 3
     
@@ -90,6 +94,6 @@ files:
     Truncated line
     Truncated line
     End line 1
-    End line 1
-    End line 1
-    End line 1
+    End line 2
+    End line 3
+    End line 4

pkg/dyff/output_human.go

@@ -371,14 +371,18 @@ func (report *HumanReport) writeStringDiff(output stringWriter, from string, to
 					continue
 				}
 				// add amount of unchanged lines as configured
-				lines := strings.Split(strings.TrimSuffix(d.Text, "\n"), "\n")
+				lines := strings.Split(d.Text, "\n")
 				lower := int(math.Min(float64(len(lines)), float64(multilineContextLines)))
 				upper := len(lines) - multilineContextLines
+				// if string ends with \n we need to display one more line on the upper limit
+				if strings.HasSuffix(d.Text, "\n") {
+					upper--
+				}
 				var val string
 				if upper <= lower {
 					val = strings.Join(lines, "\n")
 				} else {
-					val = fmt.Sprintf("%s\n\n[%s unchanged)]\n\n%s\n",
+					val = fmt.Sprintf("%s\n\n[%s unchanged)]\n\n%s",
 						strings.Join(lines[:lower], "\n"),
 						text.Plural((upper-lower), "line"),
 						strings.Join(lines[upper:], "\n"))