From 4ef085e27b48eec782c291dee7ac53a8fa6193a4 Mon Sep 17 00:00:00 2001
From: skinnyfit <richard@soupish.net>
Date: Mon, 9 Oct 2017 22:20:28 +0100
Subject: [PATCH] Support negative axes

---
 lib/squid/axis.rb |  1 +
 spec/axis_spec.rb | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/lib/squid/axis.rb b/lib/squid/axis.rb
index 5f63c74..58016aa 100644
--- a/lib/squid/axis.rb
+++ b/lib/squid/axis.rb
@@ -46,6 +46,7 @@ def min
 
     def max
       if @data.any? && values.last && values.last.any?
+        return 0 if min < 0 && values.last.max <= 0
         closest_step_to values.last.max
       end
     end
diff --git a/spec/axis_spec.rb b/spec/axis_spec.rb
index 754b22f..7c60bab 100644
--- a/spec/axis_spec.rb
+++ b/spec/axis_spec.rb
@@ -99,4 +99,29 @@
       it { expect(width).to eq 14 }
     end
   end
+
+  describe '#minmax' do
+    subject(:axis) { Squid::Axis.new series, options }
+    let(:minmax) { axis.minmax }
+
+    describe 'given all-zero series' do
+      let(:series) { [0, 0, 0] }
+      it { expect(minmax).to eq [0, steps] }
+    end
+
+    describe 'given positive series' do
+      let(:series) { [0, 10, 12] }
+      it { expect(minmax).to eq [0, 12] }
+    end
+
+    describe 'given negative series' do
+      let(:series) { [0, -10, -12] }
+      it { expect(minmax).to eq [-12, 0] }
+    end
+
+    describe 'given mixed series' do
+      let(:series) { [0, -10, 12] }
+      it { expect(minmax).to eq [-10, 12] }
+    end
+  end
 end