Update doc diff

docs/spec/runner/error_messages.md

@@ -98,15 +98,14 @@ A diff output (similar to git diff) could be used instead to display the error.
 
 ```
 error: Assert body value
-  --> test.hurl:4:1
+  --> test.hurl:8:1
    |
    | GET http://localhost:8000/test
    | ...
- 4 | @@ -2,7 +2,7 @@
    |    "first_name": "John",
    |    "last_name": "Smith",
    |    "is_alive": true,
-   | -  "age": 27,
+ 8 | -  "age": 27,
    | +  "age": 28,
    |    "address": {
    |    "street_address": "21 2nd Street",
@@ -130,8 +129,7 @@ error: Assert body value
    |
    | GET http://localhost:8000/test
    | ...
- 4 | @@ -1 +1 @@
-   | -Hello World!
+ 4 | -Hello World!
    | +Hi World!
    |
 ```
@@ -145,6 +143,146 @@ The color is necessary here to see the additional whitespace.
 We could also add a cli option to show explicitly "invisible characters".
 
 
+### Display more or less context lines before first change
+
+## Change at line 1
+
+Standard unified diff
+
+```
+@@ -1,4 +1,4 @@
+-{
++[
+   "first_name": "John",
+   "last_name": "Smith",
+   "is_alive": true,
+```
+
+Hurl Output
+
+```
+error: Assert body value
+  --> test.hurl:4:1
+   |
+   | GET http://localhost:8000/test
+ 4 | -{
+   | +[  
+   |    "first_name": "John",
+   |    "last_name": "Smith",
+   |    "is_alive": true,
+```
 
 
+## Change at line 2
 
+
+Standard unified diff
+
+```
+@@ -1,5 +1,5 @@
+ {
+-  "first_name": "John",
++  "first_name": "Bob",
+   "last_name": "Smith",
+   "is_alive": true,
+   "age": 27,
+```
+
+Hurl Output
+
+```
+error: Assert body value
+  --> test.hurl:5:1
+   |
+   | GET http://localhost:8000/test
+   |  {
+ 5 |-   "first_name": "John",
+   |+   "first_name": "Bob",
+   |    "is_alive": true,
+   |    "age": 27,
+```
+
+
+## Change at line 3
+
+Standard unified diff
+
+```
+@@ -1,6 +1,6 @@
+ {
+   "first_name": "John",
+-  "last_name": "Smith",
++  "last_name": "Smiths",
+   "is_alive": true,
+   "age": 27,
+   "address": {
+```
+
+Hurl Output
+
+```
+error: Assert body value
+  --> test.hurl:6:1
+   |
+   | GET http://localhost:8000/test
+   | {
+   |   "first_name": "John",
+6  |-  "last_name": "Smith",
+   |+  "last_name": "Smiths",
+   |   "is_alive": true,
+   |   "age": 27,
+   |   "address": {
+```
+
+
+### Display several diff Hunks
+
+
+Standard Unified Diff
+
+```
+@@ -2,7 +2,7 @@
+   "first_name": "John",
+   "last_name": "Smith",
+   "is_alive": true,
+-  "age": 27,
++  "age": 28,
+   "address": {
+     "street_address": "21 2nd Street",
+     "city": "New York",
+@@ -22,7 +22,7 @@
+   "children": [
+     "Catherine",
+     "Thomas",
+-    "Trevor"
++    "Bob"
+   ],
+   "spouse": null
+ }
+```
+
+```
+error: Assert body value
+  --> test.hurl:8:1
+   |
+   | GET http://localhost:8000/test
+   | ...
+   |   "first_name": "John",
+   |-  "last_name": "Smith",
+   |   "is_alive": true,
+ 8 |-  "age": 27,
+   |+  "age": 28,
+   |   "address": {
+   |     "street_address": "21 2nd Street",
+   |     "city": "New York",
+   | ...
+   |   "children": [
+   |     "Catherine",
+   |     "Thomas",
+28 |-    "Trevor"
+   |+    "Bob"
+   |   ],
+   |   "spouse": null
+   | }  
+  
+```