tests: improve PDF benchmarks

Factorize and use a proper separate test for each benchmark.

Note: only open the 9 fist pages (reduce memory so benchmarks
can be run on more limited memory devices, like the Kindle).

spec/unit/benchmark.lua

@@ -13,31 +13,33 @@ local function logDuration(filename, pageno, dur)
     end
 end
 
-describe("PDF rendering benchmark", function()
-    local sample_pdf = "spec/front/unit/data/sample.pdf"
-    local doc = DocumentRegistry:openDocument(sample_pdf)
-    for pageno = 1, math.min(10, doc.info.number_of_pages) do
-        local secs, usecs = util.gettime()
-        assert.truthy(doc:renderPage(pageno, nil, 1, 0, 1.0))
-        local nsecs, nusecs = util.gettime()
-        local dur = nsecs - secs + (nusecs - usecs) / 1000000
-        logDuration("pdf_rendering.log", pageno, dur)
-    end
-    doc:close()
-end)
+describe("PDF benchmark:", function()
 
-describe("PDF reflowing benchmark", function()
-    local sample_pdf = "spec/front/unit/data/sample.pdf"
-    local doc = DocumentRegistry:openDocument(sample_pdf)
-    doc.configurable.text_wrap = 1
-    for pageno = 1, math.min(10, doc.info.number_of_pages) do
-        local secs, usecs = util.gettime()
-        assert.truthy(doc:renderPage(pageno, nil, 1, 0, 1.0))
-        local nsecs, nusecs = util.gettime()
-        local dur = nsecs - secs + (nusecs - usecs) / 1000000
-        logDuration("pdf_reflowing.log", pageno, dur)
+    local function benchmark(logfile, reflow)
+        local sample_pdf = "spec/front/unit/data/sample.pdf"
+        local doc = DocumentRegistry:openDocument(sample_pdf)
+        if reflow then
+            doc.configurable.text_wrap = 1
+        end
+        for pageno = 1, math.min(9, doc.info.number_of_pages) do
+            local secs, usecs = util.gettime()
+            assert.truthy(doc:renderPage(pageno, nil, 1, 0, 1.0))
+            local nsecs, nusecs = util.gettime()
+            local dur = nsecs - secs + (nusecs - usecs) / 1000000
+            logDuration(logfile, pageno, dur)
+        end
+        doc:close()
+        if reflow then
+            doc.configurable.text_wrap = 0
+        end
     end
-    doc:close()
-    doc.configurable.text_wrap = 0
-end)
 
+    it("rendering", function()
+        benchmark("pdf_rendering.log", false)
+    end)
+
+    it("reflowing", function()
+        benchmark("pdf_reflowing.log", true)
+    end)
+
+end)