diagram-generator: be more quiet

Ensures that `make test` does not print to stdout.

Author: tarleb

Diff for: diagram-generator/Makefile

@@ -4,7 +4,6 @@ test: sample.html
 sample.html: sample.md
 	@pandoc --self-contained \
 	    --lua-filter=diagram-generator.lua \
-	    --metadata=activatePythonPath:"python3 --version" \
 	    --metadata=pythonPath:"python3" \
 	    --metadata=title:"README" \
 	    --output=$@ $<

Diff for: diagram-generator/README.md

@@ -156,7 +156,7 @@ examples](http://www.texample.net/tikz/examples/parallelepiped/) by
 ~~~~~~~~~~~~~~~~
 
 ### Python
-In order to use Python to generate an diagram, your Python code must store the
+In order to use Python to generate a diagram, your Python code must store the
 final image data in a temporary file with the correct format. In case you use
 matplotlib for a diagram, add the following line to do so:
 
@@ -249,4 +249,4 @@ All available meta keys:
 - `activatePythonPath`
 - `javaPath`
 - `dotPath`
-- `pdflatexPath`
+- `pdflatexPath`

Diff for: diagram-generator/diagram-generator.lua

@@ -98,7 +98,7 @@ local function tikz2image(src, filetype, additionalPackages)
     local tmpDir = "./tmp-latex/"
 
     -- Ensure, that the tmp directory exists:
-    os.execute("mkdir tmp-latex")
+    os.execute("mkdir -p tmp-latex")
 
     -- Build and write the LaTeX document:
     local f = io.open(tmp .. ".tex", 'w')
@@ -185,9 +185,11 @@ local function py2image(code, filetype)
     f:close()
 
     -- Execute Python in the desired environment:
-    os.execute(
-        pythonActivatePath .. " && " .. pythonPath .. " " .. pyfile
-    )
+    local pycmd = pythonPath .. ' ' .. pyfile
+    local command = pythonActivatePath
+      and pythonActivatePath .. ' && ' .. pycmd
+      or pycmd
+    os.execute(command)
 
     -- Try to open the written image:
     local r = io.open(outfile, 'rb')