Port tests for missing else branch to NUnit (#7209)

tests/fsharp/Compiler/ErrorMessages/MissingElseBranch.fs

@@ -0,0 +1,50 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
+
+namespace FSharp.Compiler.UnitTests
+
+open NUnit.Framework
+open FSharp.Compiler.SourceCodeServices
+
+[<TestFixture>]
+module ``Else branch is missing`` =
+
+    [<Test>]
+    let ``Fail if else branch is missing``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let x = 10
+let y =
+   if x > 10 then "test"
+            """
+            FSharpErrorSeverity.Error
+            1
+            (4, 19, 4, 25)
+            "This 'if' expression is missing an 'else' branch. Because 'if' is an expression, and not a statement, add an 'else' branch which also returns a value of type 'string'."
+
+    [<Test>]
+    let ``Fail on type error in condition``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let x = 10
+let y =
+   if x > 10 then 
+     if x <> "test" then printfn "test"
+     ()
+            """
+            FSharpErrorSeverity.Error
+            1
+            (5, 14, 5, 20)
+            "This expression was expected to have type\n    'int'    \nbut here has type\n    'string'    "
+
+    [<Test>]
+    let ``Fail if else branch is missing in nesting``() =
+        CompilerAssert.TypeCheckSingleError
+            """
+let x = 10
+let y =
+   if x > 10 then ("test")
+            """
+            FSharpErrorSeverity.Error
+            1
+            (4, 20, 4, 26)
+            "This 'if' expression is missing an 'else' branch. Because 'if' is an expression, and not a statement, add an 'else' branch which also returns a value of type 'string'."

tests/fsharp/FSharpSuite.Tests.fsproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
@@ -33,6 +33,7 @@
     <Compile Include="Compiler\ILChecker.fs" />
     <Compile Include="Compiler\CompilerAssert.fs" />
     <Compile Include="Compiler\ErrorMessages\ElseBranchHasWrongTypeTests.fs" />
+    <Compile Include="Compiler\ErrorMessages\MissingElseBranch.fs" />
     <Compile Include="Compiler\SourceTextTests.fs" />
     <Compile Include="Compiler\Language\AnonRecordTests.fs" />
     <Compile Include="Compiler\Language\SpanOptimizationTests.fs" />

tests/fsharpqa/Source/Warnings/env.lst

@@ -1,7 +1,4 @@
 	SOURCE=WrongNumericLiteral.fs # WrongNumericLiteral.fs
-	SOURCE=WarnIfMissingElseBranch.fs # WarnIfMissingElseBranch.fs
-	SOURCE=WarnIfMissingElseBranch2.fs # WarnIfMissingElseBranch2.fs
-	SOURCE=WarnIfMissingElseBranch3.fs # WarnIfMissingElseBranch3.fs
 	SOURCE=ReturnInsteadOfReturnBang.fs # ReturnInsteadOfReturnBang.fs
 	SOURCE=YieldInsteadOfYieldBang.fs # YieldInsteadOfYieldBang.fs
 	SOURCE=TupleInAbstractMethod.fs # TupleInAbstractMethod.fs