From c9230c24cebd5ebacae7eced66ee4fd599bbb5af Mon Sep 17 00:00:00 2001
From: Patrick Stevens <3138005+Smaug123@users.noreply.github.com>
Date: Mon, 16 Jun 2025 00:36:50 +0100
Subject: [PATCH] Allow line number stability too (#1)

---
 WoofWare.Expect.Test/SimpleTest.fs  | 11 +++++++++--
 WoofWare.Expect/Library.fs          | 14 +++++++-------
 WoofWare.Expect/SurfaceBaseline.txt |  4 ++--
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/WoofWare.Expect.Test/SimpleTest.fs b/WoofWare.Expect.Test/SimpleTest.fs
index 545a548..c7a20dd 100644
--- a/WoofWare.Expect.Test/SimpleTest.fs
+++ b/WoofWare.Expect.Test/SimpleTest.fs
@@ -17,7 +17,7 @@ module SimpleTest =
     let ``Example of a failing test`` () =
         expect {
             snapshot
-                "snapshot mismatch! snapshot at filepath.fs:32 (Example of a failing test) was:
+                "snapshot mismatch! snapshot at filepath.fs:99 (Example of a failing test) was:
 
 - 123
 
@@ -28,10 +28,17 @@ actual was:
             return
                 Assert
                     .Throws<Exception>(fun () ->
-                        expectWithMockedFilePath "filepath.fs" {
+                        expectWithMockedFilePath ("filepath.fs", 99) {
                             snapshot "123"
                             return 124
                         }
                     )
                     .Message
         }
+
+    [<Test>]
+    let ``Basic example`` () =
+        expect {
+            snapshot "123"
+            return 123
+        }
diff --git a/WoofWare.Expect/Library.fs b/WoofWare.Expect/Library.fs
index 12cec80..58641f3 100644
--- a/WoofWare.Expect/Library.fs
+++ b/WoofWare.Expect/Library.fs
@@ -32,8 +32,8 @@ module private Text =
 /// The builder which powers WoofWare.Expect.
 /// </summary>
 /// <remarks>You're not expected to construct this explicitly; it's a computation expression, available as <c>Builder.expect</c>.</remarks>
-/// <param name="filePathOverride">Override the file paths reported in snapshots, so that your tests can be fully stable even on failure. (You almost certainly don't want to set this.)</param>
-type ExpectBuilder (?filePathOverride : string) =
+/// <param name="sourceOverride">Override the file path and line numbers reported in snapshots, so that your tests can be fully stable even on failure. (You almost certainly don't want to set this.)</param>
+type ExpectBuilder (?sourceOverride : string * int) =
     /// Combine two `ExpectState`s. The first one is the "expected" snapshot; the second is the "actual".
     member _.Bind (state : ExpectState<unit>, f : unit -> ExpectState<'U>) : ExpectState<'U> =
         let actual = f ()
@@ -153,8 +153,8 @@ type ExpectBuilder (?filePathOverride : string) =
                 if not (JsonElement.DeepEquals (canonicalActual.RootElement, canonicalSnapshot.RootElement)) then
                     failwithf
                         "snapshot mismatch! snapshot at %s:%i (%s) was:\n\n%s\n\nactual was:\n\n%s"
-                        (filePathOverride |> Option.defaultValue source.FilePath)
-                        source.LineNumber
+                        (sourceOverride |> Option.map fst |> Option.defaultValue source.FilePath)
+                        (sourceOverride |> Option.map snd |> Option.defaultValue source.LineNumber)
                         source.MemberName
                         (canonicalSnapshot.RootElement.ToString () |> Text.predent '-')
                         (canonicalActual.RootElement.ToString () |> Text.predent '-')
@@ -165,8 +165,8 @@ type ExpectBuilder (?filePathOverride : string) =
                 if actual <> snapshot then
                     failwithf
                         "snapshot mismatch! snapshot at %s:%i (%s) was:\n\n%s\n\nactual was:\n\n%s"
-                        (filePathOverride |> Option.defaultValue source.FilePath)
-                        source.LineNumber
+                        (sourceOverride |> Option.map fst |> Option.defaultValue source.FilePath)
+                        (sourceOverride |> Option.map snd |> Option.defaultValue source.LineNumber)
                         source.MemberName
                         (snapshot |> Text.predent '-')
                         (actual |> Text.predent '+')
@@ -200,4 +200,4 @@ module Builder =
     /// You probably don't want to use this; use `expect` instead.
     /// The point of the mocked builder is to allow fully predictable testing of the WoofWare.Expect library itself.
     /// </remarks>
-    let expectWithMockedFilePath (path : string) = ExpectBuilder path
+    let expectWithMockedFilePath (path : string, line : int) = ExpectBuilder ((path, line))
diff --git a/WoofWare.Expect/SurfaceBaseline.txt b/WoofWare.Expect/SurfaceBaseline.txt
index 0312b42..06fe417 100644
--- a/WoofWare.Expect/SurfaceBaseline.txt
+++ b/WoofWare.Expect/SurfaceBaseline.txt
@@ -1,9 +1,9 @@
 WoofWare.Expect.Builder inherit obj
 WoofWare.Expect.Builder.expect [static property]: [read-only] WoofWare.Expect.ExpectBuilder
-WoofWare.Expect.Builder.expectWithMockedFilePath [static method]: string -> WoofWare.Expect.ExpectBuilder
+WoofWare.Expect.Builder.expectWithMockedFilePath [static method]: (string, int) -> WoofWare.Expect.ExpectBuilder
 WoofWare.Expect.Builder.get_expect [static method]: unit -> WoofWare.Expect.ExpectBuilder
 WoofWare.Expect.ExpectBuilder inherit obj
-WoofWare.Expect.ExpectBuilder..ctor [constructor]: string option
+WoofWare.Expect.ExpectBuilder..ctor [constructor]: (string * int) option
 WoofWare.Expect.ExpectBuilder.Bind [method]: (unit WoofWare.Expect.ExpectState, unit -> 'U WoofWare.Expect.ExpectState) -> 'U WoofWare.Expect.ExpectState
 WoofWare.Expect.ExpectBuilder.Delay [method]: (unit -> 'T WoofWare.Expect.ExpectState) -> (unit -> 'T WoofWare.Expect.ExpectState)
 WoofWare.Expect.ExpectBuilder.Return [method]: 'T -> 'T WoofWare.Expect.ExpectState