Make the project a positional argument

Example.Tests/CalculatorTests.fs

@@ -6,17 +6,17 @@ open Xunit
 
 type CalculatorTests() =
     [<Fact>]
-    [<MutationCase("calc-add-one", "example-tests/Example.Tests/Calculator.fs", 4, "value + 1", "value - 1")>]
+    [<MutationCase("calc-add-one", "Example.Tests/Calculator.fs", 4, "value + 1", "value - 1")>]
     member _.AddOne_increments() =
         Assert.Equal(42, Calculator.addOne 41)
 
     [<Fact>]
-    [<MutationCase("calc-abs-diff-branch", "example-tests/Example.Tests/Calculator.fs", 7, "left - right", "right - left")>]
+    [<MutationCase("calc-abs-diff-branch", "Example.Tests/Calculator.fs", 7, "left - right", "right - left")>]
     member _.AbsoluteDifference_preserves_order() =
         Assert.Equal(7, Calculator.absoluteDifference 10 3)
 
     [<Fact>]
-    [<MutationCase("calc-leap-year-century", "example-tests/Example.Tests/Calculator.fs", 10, "year % 100 <> 0", "year % 100 = 0")>]
+    [<MutationCase("calc-leap-year-century", "Example.Tests/Calculator.fs", 10, "year % 100 <> 0", "year % 100 = 0")>]
     member _.LeapYear_handles_centuries() =
         Assert.True(Calculator.isLeapYear 2000)
         Assert.False(Calculator.isLeapYear 1900)

verify-coverage-mutants.fsx

@@ -1,3 +1,4 @@
+#!/usr/bin/env -S dotnet fsi
 open System
 open System.IO
 open System.Reflection
@@ -24,13 +25,14 @@ type Command =
 
 type Options =
     { Configuration: string
+      ProjectPath: string
+      BuildArgs: string list
       NoBuild: bool
       Command: Command }
 
-let projectPath = "Example.Tests"
-let targetFramework = "net10.0"
-let projectDirectory = "example-tests"
-let testProjectPath = Path.Combine(projectDirectory, "Example.Tests", "Example.Tests.fsproj")
+type ProjectInfo =
+    { RelativeProjectPath: string
+      AbsoluteProjectPath: string }
 
 let fail message =
     eprintfn "%s" message
@@ -76,30 +78,67 @@ let repoRoot =
     if exitCode <> 0 then fail stderr
     stdout.Trim()
 
-let makeRelativePath (path: string) =
-    if Path.IsPathRooted path then Path.GetRelativePath(repoRoot, path) else path
-
 let parseArgs (args: string list) =
-    let rec loop configuration noBuild remaining =
+    let usage () =
+        fail "Usage: verify-coverage-mutants.fsx <path/to/project.fsproj> [--configuration Debug|Release] [--build-arg <value> ...] [--no-build] [--list | --show <id> | --run [id...]]"
+
+    let rec loop configuration projectPath buildArgs noBuild remaining =
         match remaining with
-        | [] -> { Configuration = configuration; NoBuild = noBuild; Command = Run [] }
-        | "--configuration" :: value :: tail -> loop value noBuild tail
-        | "--no-build" :: tail -> loop configuration true tail
-        | "--list" :: tail when tail.IsEmpty -> { Configuration = configuration; NoBuild = noBuild; Command = List }
-        | "--show" :: id :: tail when tail.IsEmpty -> { Configuration = configuration; NoBuild = noBuild; Command = Show id }
-        | "--run" :: tail -> { Configuration = configuration; NoBuild = noBuild; Command = Run tail }
-        | value :: tail when not (value.StartsWith "--") -> { Configuration = configuration; NoBuild = noBuild; Command = Run (value :: tail) }
-        | _ -> fail "Usage: dotnet fsi verify-coverage-mutants.fsx [--configuration Debug|Release] [--no-build] [--list | --show <id> | --run [id...]]"
-    loop "Debug" false args
+        | [] -> { Configuration = configuration; ProjectPath = projectPath; BuildArgs = List.rev buildArgs; NoBuild = noBuild; Command = Run [] }
+        | "--configuration" :: value :: tail -> loop value projectPath buildArgs noBuild tail
+        | "--build-arg" :: value :: tail -> loop configuration projectPath (value :: buildArgs) noBuild tail
+        | "--no-build" :: tail -> loop configuration projectPath buildArgs true tail
+        | "--list" :: tail when tail.IsEmpty -> { Configuration = configuration; ProjectPath = projectPath; BuildArgs = List.rev buildArgs; NoBuild = noBuild; Command = List }
+        | "--show" :: id :: tail when tail.IsEmpty -> { Configuration = configuration; ProjectPath = projectPath; BuildArgs = List.rev buildArgs; NoBuild = noBuild; Command = Show id }
+        | "--run" :: tail -> { Configuration = configuration; ProjectPath = projectPath; BuildArgs = List.rev buildArgs; NoBuild = noBuild; Command = Run tail }
+        | value :: tail when not (value.StartsWith "--") -> { Configuration = configuration; ProjectPath = projectPath; BuildArgs = List.rev buildArgs; NoBuild = noBuild; Command = Run (value :: tail) }
+        | _ -> usage ()
+
+    match args with
+    | projectPath :: tail when not (projectPath.StartsWith "--") -> loop "Debug" projectPath [] false tail
+    | _ -> usage ()
 
 let options = parseArgs (fsi.CommandLineArgs |> Array.skip 1 |> Array.toList)
 
-let assemblyPath =
-    Path.Combine(repoRoot, projectDirectory, "Example.Tests", "bin", options.Configuration, targetFramework, "Example.Tests.dll")
+let ensureWithinRepo (path: string) =
+    let relativePath = Path.GetRelativePath(repoRoot, path)
+    if relativePath = ".." || relativePath.StartsWith($"..{Path.DirectorySeparatorChar}") then
+        fail $"Project path must be inside the repository: {path}"
+    relativePath
+
+let loadProjectInfo (projectPath: string) =
+    let absoluteProjectPath =
+        if Path.IsPathRooted projectPath then projectPath
+        else Path.GetFullPath(Path.Combine(Environment.CurrentDirectory, projectPath))
+
+    if not (File.Exists absoluteProjectPath) then
+        fail $"Project file not found: {absoluteProjectPath}"
+
+    let relativeProjectPath = ensureWithinRepo absoluteProjectPath
+    { RelativeProjectPath = relativeProjectPath
+      AbsoluteProjectPath = absoluteProjectPath }
+
+let project =
+    loadProjectInfo options.ProjectPath
+
+let targetPathForProject (workingDirectory: string) (projectPath: string) =
+    let exitCode, stdout, stderr =
+        captureProcess workingDirectory "dotnet" [ "msbuild"; projectPath; "--getProperty:TargetPath"; $"-property:Configuration={options.Configuration}" ]
+    if exitCode <> 0 then fail stderr
+    let targetPath = stdout.Trim()
+    if String.IsNullOrWhiteSpace targetPath then
+        fail $"MSBuild did not return a TargetPath for {projectPath}."
+    targetPath
+
+let assemblyPath = targetPathForProject repoRoot project.AbsoluteProjectPath
+
+let buildArgs projectPath =
+    [ "build"; projectPath; "--configuration"; options.Configuration; "--nologo" ]
+    @ options.BuildArgs
 
 let ensureBuilt () =
     if not options.NoBuild then
-        let exitCode = runProcess repoRoot "dotnet" [ "build"; testProjectPath; "--configuration"; options.Configuration; "--nologo" ]
+        let exitCode = runProcess repoRoot "dotnet" (buildArgs project.RelativeProjectPath)
         if exitCode <> 0 then fail "dotnet build failed."
     if not (File.Exists assemblyPath) then
         fail $"Compiled test assembly not found at {assemblyPath}."
@@ -209,7 +248,7 @@ let runMutation (mutation: MutationCase) =
 
     printfn "==> %s: %s" mutation.Id mutation.TestName
     let buildExitCode =
-        runProcess worktreePath "dotnet" [ "build"; testProjectPath; "--configuration"; options.Configuration; "--nologo" ]
+        runProcess worktreePath "dotnet" (buildArgs project.RelativeProjectPath)
 
     let outcome =
         if buildExitCode <> 0 then
@@ -217,7 +256,7 @@ let runMutation (mutation: MutationCase) =
             BuildFailed
         else
             let testExitCode =
-                runProcess worktreePath "dotnet" [ "test"; testProjectPath; "--configuration"; options.Configuration; "--filter"; testFilter mutation; "--no-build"; "--nologo" ]
+                runProcess worktreePath "dotnet" [ "test"; project.RelativeProjectPath; "--configuration"; options.Configuration; "--filter"; testFilter mutation; "--no-build"; "--nologo" ]
 
             if testExitCode = 0 then
                 printfn "SURVIVED  %s" mutation.Id