Produce debug output when tests fail

Author: eschnett

test/ssl.jl

@@ -10,6 +10,24 @@ function curl_write_cb(curlbuf::Ptr{Cvoid}, s::Csize_t, n::Csize_t, p_ctxt::Ptr{
     return sz::Csize_t
 end
 
+# Setup the callback function to collect debug information
+const infotype_str = Dict(
+    0 => "CURLINFO_TEXT",
+    1 => "CURLINFO_HEADER_IN",
+    2 => "CURLINFO_HEADER_OUT",
+    3 => "CURLINFO_DATA_IN",
+    4 => "CURLINFO_DATA_OUT",
+    5 => "CURLINFO_SSL_DATA_IN",
+    6 => "CURLINFO_SSL_DATA_OUT",
+)
+
+function curl_debug_cb(handle::Ptr{Cvoid}, type::Cint, data::Ptr{Cvoid}, sz::Csize_t, clientp::Ptr{Cvoid})
+    debug_buffer = unsafe_pointer_to_objref(clientp)::IOBuffer
+    data = UInt8[unsafe_load(reinterpret(Ptr{Cuchar}, data), n) for n in 1:sz]
+    println(debug_buffer, "$(infotype_str[type]) \"$(String(data))\"")
+    return Cint(0)
+end
+
 @testset "SSL verify" begin
     # Set up the write function to consume the curl output so we don't see it in the
     # test output
@@ -27,11 +45,27 @@ end
     curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1)
     curl_easy_setopt(curl, CURLOPT_CAINFO, LibCURL.cacert)
 
-    @testset "SSL Success" begin
-        res = curl_easy_perform(curl)
-        @test res == CURLE_OK
-    end
+    # For debugging -- we see that `res ≠ CURLE_OK` below and want to know why
+    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1)
+    c_curl_debug_cb = @cfunction(
+        curl_debug_cb,
+        Cint,
+        (Ptr{Cvoid}, Cint, Ptr{Cvoid}, Csize_t, Ptr{Cvoid})
+    )
+    debug_buffer = IOBuffer()
+    GC.@preserve debug_buffer begin
+        curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, c_curl_debug_cb)
+        curl_easy_setopt(curl, CURLOPT_DEBUGDATA, pointer_from_objref(debug_buffer))
 
+        @testset "SSL Success" begin
+            res = curl_easy_perform(curl)
+            if !(res == CURLE_OK)
+                println("CURL debug output:\n")
+                print(takestring!(debug_buffer))
+            end
+            @test res == CURLE_OK
+        end
+    end
 end
 
 curl_easy_cleanup(curl)