tests - Add some simple intermediate markdown snapshot test cases

This way we check that a basic markdown intermediate is as expected, and with no unprocessed cell div  :::

Author: cderv

tests/docs/julia/intermediate-markdown-output/output-cell-div.markdown.md.snapshot

@@ -0,0 +1,24 @@
+---
+title: "Untitled"
+format: markdown
+keep-md: true
+engine: julia
+---
+
+This does it:
+
+::: {.cell execution_count=1}
+``` {.julia .cell-code}
+1 + 1
+```
+
+::: {.cell-output .cell-output-display execution_count=1}
+```
+2
+```
+:::
+:::
+
+
+Other content
+

tests/docs/julia/intermediate-markdown-output/output-cell-div.qmd

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+---
+title: "Untitled"
+format: markdown
+keep-md: true
+engine: julia
+---
+
+This does it:
+```{julia}
+1 + 1
+```
+Other content

tests/docs/jupyter/intermediate-markdown-output/output-cell-div.markdown.md.snapshot

@@ -0,0 +1,23 @@
+---
+title: "Untitled"
+format: markdown
+keep-md: true
+---
+
+This does it:
+
+::: {.cell execution_count=1}
+``` {.python .cell-code}
+1 + 1
+```
+
+::: {.cell-output .cell-output-display execution_count=1}
+```
+2
+```
+:::
+:::
+
+
+Other content
+

tests/docs/jupyter/intermediate-markdown-output/output-cell-div.qmd

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+---
+title: "Untitled"
+format: markdown
+keep-md: true
+---
+
+This does it:
+```{python}
+1 + 1
+```
+Other content

tests/docs/knitr/intermediate-markdown-output/output-cell-div.markdown.md.snapshot

@@ -0,0 +1,25 @@
+---
+title: "Untitled"
+format: markdown
+keep-md: true
+---
+
+This does it:
+
+::: {.cell}
+
+```{.r .cell-code}
+1 + 1
+```
+
+::: {.cell-output .cell-output-stdout}
+
+```
+[1] 2
+```
+
+
+:::
+:::
+
+Other content

tests/docs/knitr/intermediate-markdown-output/output-cell-div.qmd

@@ -0,0 +1,11 @@
+---
+title: "Untitled"
+format: markdown
+keep-md: true
+---
+
+This does it:
+```{r}
+1 + 1
+```
+Other content

tests/smoke/engine/intermediate-output-markdown.test.ts

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+import { dirname, join } from "path";
+import { ensureSnapshotMatches, noErrors, printsMessage } from "../../verify.ts";
+import { fileLoader } from "../../utils.ts";
+import { safeRemoveIfExists } from "../../../src/core/path.ts";
+import { testRender } from "../render/render.ts";
+
+// Define engines to test
+const engines = [
+  { name: "knitr" },
+  { name: "jupyter" },
+  { name: "julia" }
+];
+
+// Run tests for each engine
+engines.forEach(engine => {
+  // Test for engine
+  const inputQmd = fileLoader(engine.name, "intermediate-markdown-output")("output-cell-div.qmd", "markdown");
+  const md = join(dirname(inputQmd.input), "output-cell-div.markdown.md");
+  testRender(inputQmd.input, "markdown", true, [
+    noErrors,
+    // Lua Warning are in INFO
+    printsMessage({ level: "INFO", regex: /WARNING \(.*\)\s+The following string was found in the document: :::/, negate: true}),
+    ensureSnapshotMatches(md)
+  ], { 
+    teardown: async () => { 
+      safeRemoveIfExists(md); 
+    } });
+});
+