Update JSONReportFormatter: report all str attribs; don't print "# No events processed" since that's not valid JSON; rename output.t to json.t.

t/pt-query-digest/json.t

@@ -0,0 +1,55 @@
+#!/usr/bin/env perl
+
+BEGIN {
+   die "The PERCONA_TOOLKIT_BRANCH environment variable is not set.\n"
+      unless $ENV{PERCONA_TOOLKIT_BRANCH} && -d $ENV{PERCONA_TOOLKIT_BRANCH};
+   unshift @INC, "$ENV{PERCONA_TOOLKIT_BRANCH}/lib";
+};
+
+use strict;
+use warnings FATAL => 'all';
+use English qw(-no_match_vars);
+use Test::More;
+
+use PerconaTest;
+require "$trunk/bin/pt-query-digest";
+
+no warnings 'once';
+local $JSONReportFormatter::sorted_json = 1;
+local $JSONReportFormatter::pretty_json = 1;
+
+my @args    = qw(--output json);
+my $sample  = "$trunk/t/lib/samples";
+my $results = "t/pt-query-digest/samples";
+
+ok(
+   no_diff(
+      sub { pt_query_digest::main(@args, "$sample/slowlogs/empty") },
+      "$results/empty_report.txt",
+   ),
+   'json output for empty log'
+) or diag($test_diff);
+
+ok(
+   no_diff(
+      sub { pt_query_digest::main(@args, "$sample/slowlogs/slow002.txt") },
+      "$results/output_json_slow002.txt"
+   ),
+   'json output for slow002'
+);
+
+# --type tcpdump
+
+ok(
+   no_diff(
+      sub { pt_query_digest::main(qw(--type tcpdump --limit 10 --watch-server 127.0.0.1:12345),
+                                  @args, "$sample/tcpdump/tcpdump021.txt") },
+      "$results/output_json_tcpdump021.txt",
+   ),
+   'json output for for tcpdump021',
+);
+
+# #############################################################################
+# Done.
+# #############################################################################
+done_testing;