Refacto error_string in order to support diff messages

integration/hurl/tests_failed/assert_newline.err

@@ -5,7 +5,7 @@ error: Assert body value
    | ...
 10 | <p>Hello</p>
    | ^ actual value is <<p>Hello</p>
-
->
+   |
+   |   >
    |
 

integration/hurl/tests_failed/assert_value_error.err

@@ -76,9 +76,9 @@ error: Assert failure
    | ...
 11 | jsonpath "$.line_terminator" == "\r\n"
    |   actual:   string <
-   |   >
+   |>
    |   expected: string <
-   |   >
+   |>
    |
 
 error: Assert failure

integration/hurl/tests_failed/assert_value_error.out.pattern

@@ -48,7 +48,7 @@
         },
         {
           "line": 11,
-          "message": "Assert failure\n  --> tests_failed/assert_value_error.hurl:11:0\n   |\n   | GET http://localhost:8000/error-assert-value\n   | ...\n11 | jsonpath \"$.line_terminator\" == \"\\r\\n\"\n   |   actual:   string <\n   |   >\n   |   expected: string <\n   |   >\n   |",
+          "message": "Assert failure\n  --> tests_failed/assert_value_error.hurl:11:0\n   |\n   | GET http://localhost:8000/error-assert-value\n   | ...\n11 | jsonpath \"$.line_terminator\" == \"\\r\\n\"\n   |   actual:   string <\n   |>\n   |   expected: string <\n   |>\n   |",
           "success": false
         },
         {

packages/hurl/src/runner/error.rs

@@ -175,11 +175,11 @@ impl hurl_core::error::Error for Error {
                 ..
             } => {
                 let additional = if *type_mismatch {
-                    "\n>>> types between actual and expected are not consistent"
+                    "\n   >>> types between actual and expected are not consistent"
                 } else {
                     ""
                 };
-                format!("actual:   {actual}\nexpected: {expected}{additional}")
+                format!("   actual:   {actual}\n   expected: {expected}{additional}")
             }
             RunnerError::AssertHeaderValueError { actual } => {
                 format!("actual value is <{actual}>")
@@ -257,6 +257,14 @@ impl hurl_core::error::Error for Error {
             }
         }
     }
+
+    fn show_source_line(&self) -> bool {
+        true
+    }
+
+    fn show_caret(&self) -> bool {
+        !matches!(&self.inner, RunnerError::AssertFailure { .. })
+    }
 }
 
 impl From<HttpError> for RunnerError {