From bcb8dfd42f14a8fd0a6507d26abec2c8d898a4e8 Mon Sep 17 00:00:00 2001
From: Marc Cousin <marc.cousin@people-doc.com>
Date: Sun, 4 Feb 2018 18:16:32 +0100
Subject: [PATCH 1/2] create table_constraint_checksum function for pg_tapgen

---
 sql/pgtap.sql.in | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sql/pgtap.sql.in b/sql/pgtap.sql.in
index 784a44c5b..d1ba83bce 100644
--- a/sql/pgtap.sql.in
+++ b/sql/pgtap.sql.in
@@ -2376,6 +2376,17 @@ RETURNS TEXT AS $$
     SELECT col_has_check( $1, $2, 'Column ' || quote_ident($1) || '(' || quote_ident($2) || ') should have a check constraint' );
 $$ LANGUAGE sql;
 
+-- table_constraint_checksum ( schema, table, conname, contype, checksum, description)
+CREATE OR REPLACE FUNCTION table_constraint_checksum (NAME, NAME, NAME, char, text, text)
+RETURNS TEXT AS $$
+  SELECT is(md5 ( pg_get_constraintdef(oid)), $5, $6)
+  FROM pg_constraint
+  WHERE connamespace=(SELECT oid FROM pg_namespace WHERE nspname=$1)
+    AND conrelid=$2::regclass
+    AND conname=$3
+    AND contype=$4;
+$$ LANGUAGE sql;
+
 -- fk_ok( fk_schema, fk_table, fk_column[], pk_schema, pk_table, pk_column[], description )
 CREATE OR REPLACE FUNCTION fk_ok ( NAME, NAME, NAME[], NAME, NAME, NAME[], TEXT )
 RETURNS TEXT AS $$

From ca2318b099204f9704f2e286d074b27553dad51a Mon Sep 17 00:00:00 2001
From: Marc Cousin <marc.cousin@people-doc.com>
Date: Tue, 6 Feb 2018 16:25:10 +0100
Subject: [PATCH 2/2] Add doc for table_constraint_checksum

---
 doc/pgtap.mmd | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/doc/pgtap.mmd b/doc/pgtap.mmd
index e348b63f0..33cc83961 100644
--- a/doc/pgtap.mmd
+++ b/doc/pgtap.mmd
@@ -4671,6 +4671,32 @@ that do have check constraints, if any:
 Just like `col_is_pk()`, except that it test that the column or array of
 columns have a check constraint on them.
 
+### `table_constraint_checksum` ###
+
+  SELECT table_constraint_checksum ( :schema, :table, :conname, :contype, :checksum, :description);
+
+**Parameters**
+
+`:schema`
+: Schema of the table owning the constraint.
+
+`:table`
+: Name of the table owning the constraint.
+
+`:conname`
+: Name of the constraint itself.
+
+`:contype`
+: Type of the constraint: c = check constraint, f = foreign key constraint,
+p = primary key constraint, u = unique constraint, t = constraint trigger,
+x = exclusion constraint.
+
+`:checksum`
+: Checksum of the constraint. Generated with md5(pg_get_constraintdef(oid)) from pg_constraint.
+
+`:description`
+: A short description of the test.
+
 ### `index_is_unique()` ###
 
     SELECT index_is_unique( :schema, :table, :index, :description );