From 671a680277b33fa84b64f6a985893f5d084b609b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Motiejus=20Jak=C5=A1tys?= <motiejus@jakstys.lt>
Date: Wed, 19 May 2021 22:57:45 +0300
Subject: [PATCH] unit tests + "last bend" bugfix

---
 tests.sql | 21 +++++++++++++++++----
 wm.sql    |  7 +++++++
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/tests.sql b/tests.sql
index 8e05135..fe09dbd 100644
--- a/tests.sql
+++ b/tests.sql
@@ -1,10 +1,23 @@
+create schema if not exists test;
 \i wm.sql
 
+-- https://stackoverflow.com/questions/19982373/which-tools-libraries-do-you-use-to-unit-test-your-pl-pgsql
+CREATE OR REPLACE FUNCTION assert_equals(expected anyelement, actual anyelement) RETURNS void AS $$
+begin
+  if expected = actual or (expected is null and actual is null) then
+    --do nothing
+  else
+    raise exception 'Assertion Error. Expected <%> but was <%>', expected, actual;
+  end if;
+end $$ LANGUAGE plpgsql;
+
 drop table if exists figures;
 create table figures (name text, way geometry);
 insert into figures (name, way) values ('fig3', ST_GeomFromText('LINESTRING(0 0, 12 0, 13 4, 20 2, 20 0, 32 0, 33 10, 38 16, 43 15, 44 10, 44 0, 60 0)'));
+insert into figures (name, way) values ('fig3-1', ST_GeomFromText('LINESTRING(0 0, 12 0, 13 4, 20 2, 20 0, 32 0, 33 10, 38 16, 43 15, 44 10, 44 0)'));
 
-drop table if exists bends;
-create table bends as (select * from detect_bends((select way from figures where name='fig3')));
-
---insert into figures (name, way) values ('Žeimena', (select st_linemerge(st_union(p.way)) from planet_osm_line p where p.name = 'Žeimena'))
+do $$
+begin
+  perform assert_equals(3::bigint, (select count(1) from detect_bends((select way from figures where name='fig3'))));
+  perform assert_equals(3::bigint, (select count(1) from detect_bends((select way from figures where name='fig3-1'))));
+end $$ language plpgsql;
diff --git a/wm.sql b/wm.sql
index a6c2194..ba1612e 100644
--- a/wm.sql
+++ b/wm.sql
@@ -36,5 +36,12 @@ begin
     end if;
     prev_sign = cur_sign;
   end loop;
+
+  -- the last bend may be lost if there is no "final" inflection angle.
+  -- to avoid that, return the last bend if the last accumulation has >3
+  -- vertices.
+  if (select count(1) from ((select st_dumppoints(bend) as a)) b) >= 3 then
+    return next;
+  end if;
 end
 $$ language plpgsql;