test pynb parsing

Author: nhirschey

src/FSharp.Formatting.Literate/ParsePynb.fs

@@ -138,9 +138,11 @@ module internal ParsePynb =
         | "code" -> getCode cell
         | _ -> failwith $"unknown cell type {cell_type}"
 
-    let ipynbToMarkdown ipynbFile =
-        let json = JsonDocument.Parse(File.ReadAllText(ipynbFile))
+    let pynbStringToMarkdown (ipynb: string) =
+        let json = JsonDocument.Parse(ipynb)
 
         json.RootElement.GetProperty("cells").EnumerateArray()
         |> Seq.map (parseCell >> (fun x -> x.ToMarkdown()))
-        |> String.concat "\n\n"
+        |> String.concat ""
+
+    let pynbToMarkdown ipynbFile = ipynbFile |> File.ReadAllText |> pynbStringToMarkdown

tests/FSharp.Literate.Tests/LiterateTests.fs

@@ -1433,6 +1433,34 @@ let goodbye = 2
 
     pynb2 |> shouldEqual expected2
 
+[<Test>]
+let ``md --> pynb --> md comes back the same`` () =
+    let mdIn = """Heading
+=======
+
+|  Col1 | Col2 |
+|:----:|------|
+|  Table with heading cell A1   | Table with heading cell B1    |
+|  Table with heading cell A2   | Table with heading cell B2    |
+
+```fsharp
+let add a b = a + b
+```
+
+```csharp
+```
+
+```python
+```
+"""
+    let mdOut = 
+        Literate.ParseMarkdownString(mdIn, 
+                                     parseOptions = 
+                                        (MarkdownParseOptions.ParseCodeAsOther
+                                         ||| MarkdownParseOptions.ParseNonCodeAsOther))
+        |> Literate.ToPynb 
+        |> ParsePynb.pynbStringToMarkdown
+    mdOut |> shouldEqual mdIn
 
 [<Test>]
 let ``Script output is exactly right`` () =