Add regression test for $PSDebugContext in prompt function

Author: andyleejordan

test/PowerShellEditorServices.Test.Shared/Debugging/PSDebugContextTest.ps1

@@ -0,0 +1,11 @@
+$promptSawDebug = $false
+
+function prompt {
+    if (Test-Path variable:/PSDebugContext -ErrorAction SilentlyContinue) {
+        $promptSawDebug = $true
+    }
+
+    return "$promptSawDebug > "
+}
+
+Write-Host "Debug over"

test/PowerShellEditorServices.Test/Debugging/DebugServiceTests.cs

@@ -501,6 +501,24 @@ public async Task DebuggerRunsCommandsWhileStopped()
             Assert.Equal(17, (await executeTask.ConfigureAwait(true))[0]);
         }
 
+        // Regression test asserting that the PSDebugContext variable is available when running the
+        // "prompt" function. While we're unable to test the REPL loop, this still covers the
+        // behavior as I verified that it stepped through "ExecuteInDebugger" (which was the
+        // original problem).
+        [Fact]
+        public async Task DebugContextAvailableInPrompt()
+        {
+            await debugService.SetCommandBreakpointsAsync(
+                new[] { CommandBreakpointDetails.Create("Write-Host") }).ConfigureAwait(true);
+
+            ScriptFile testScript = GetDebugScript("PSDebugContextTest.ps1");
+            Task _ = ExecutePowerShellCommand(testScript.FilePath);
+            AssertDebuggerStopped(testScript.FilePath, 11);
+
+            VariableDetails prompt = await debugService.EvaluateExpressionAsync("prompt", false).ConfigureAwait(true);
+            Assert.Equal("\"True > \"", prompt.ValueString);
+        }
+
         [Fact]
         public async Task DebuggerVariableStringDisplaysCorrectly()
         {