Use travis test config variable 0/1 instead of blank strings

Travis web interface doesn't allow anymore to set an empty string as
variable value.

doc/release.rst

@@ -16,7 +16,7 @@ How to make a psycopg2 release
     $ export VERSION=2.7
 
 - In the `Travis settings`__ you may want to be sure that the variables
-  ``TEST_PAST`` and ``TEST_FUTURE`` are set to a nonzero string to check all
+  ``TEST_PAST`` and ``TEST_FUTURE`` are set to 1 to check all
   the supported postgres version.
 
 .. __: https://travis-ci.org/psycopg/psycopg2/settings

scripts/travis_prepare.sh

@@ -116,7 +116,7 @@ create () {
 cd /
 
 # Postgres versions supported by Travis CI
-if [[ -z "$DONT_TEST_PRESENT" ]]; then
+if (( ! "$DONT_TEST_PRESENT" )); then
     create 10
     create 9.6
     create 9.5
@@ -125,7 +125,7 @@ fi
 
 # Unsupported postgres versions that we still support
 # Images built by https://github.com/psycopg/psycopg2-wheels/tree/build-dinosaurs
-if [[ -n "$TEST_PAST" ]]; then
+if (( "$TEST_PAST" )); then
     create 7.4
     create 8.0
     create 8.1
@@ -139,6 +139,6 @@ if [[ -n "$TEST_PAST" ]]; then
 fi
 
 # Postgres built from master
-if [[ -n "$TEST_FUTURE" ]]; then
+if (( "$TEST_FUTURE" )); then
     create 11 11-master
 fi

scripts/travis_test.sh

@@ -16,7 +16,7 @@ set -e -x
 run_test () {
     VERSION=$1
     DBNAME=psycopg2_test
-    if [[ -n "$TEST_VERBOSE" ]]; then
+    if (( "$TEST_VERBOSE" )); then
         VERBOSE=--verbose
     else
         VERBOSE=
@@ -45,7 +45,7 @@ run_test () {
 }
 
 # Postgres versions supported by Travis CI
-if [[ -z "$DONT_TEST_PRESENT" ]]; then
+if (( ! "$DONT_TEST_PRESENT" )); then
     run_test 10
     run_test 9.6
     run_test 9.5
@@ -54,7 +54,7 @@ fi
 
 # Unsupported postgres versions that we still support
 # Images built by https://github.com/psycopg/psycopg2-wheels/tree/build-dinosaurs
-if [[ -n "$TEST_PAST" ]]; then
+if (( "$TEST_PAST" )); then
     run_test 9.3
     run_test 9.2
     run_test 9.1
@@ -68,6 +68,6 @@ if [[ -n "$TEST_PAST" ]]; then
 fi
 
 # Postgres built from master
-if [[ -n "$TEST_FUTURE" ]]; then
+if (( "$TEST_FUTURE" )); then
     run_test 11
 fi

tests/testutils.py

@@ -425,7 +425,7 @@ def slow(f):
     """
     @wraps(f)
     def slow_(self):
-        if os.environ.get('PSYCOPG2_TEST_FAST'):
+        if os.environ.get('PSYCOPG2_TEST_FAST', '0') != '0':
             return self.skipTest("slow test")
         return f(self)
     return slow_