Update .travis.yml configuration & add .coveragerc (#389)

* Update .travis.yml configuration

* Only do coveralls for one job

* Fix failing tests

* Tweak Mac OS build

* More tweaks to Mac OS builds

* Fix error with submitting to coveralls.io

* Add .coveragerc

* Add missing revkit dependency to .travis.yml

* Temporarily disable Mac OS and Windows builds

- Disable the builds until the project will be migrated to
  travis-ci.com due to the new credits plans on Travis-CI.

.coveragerc

@@ -0,0 +1,3 @@
+[run]
+
+omit = *_test.py

.travis.yml

@@ -1,52 +1,75 @@
-sudo: false
+# ==============================================================================
+
+addons:
+  apt:
+    sources: ['ubuntu-toolchain-r-test']
+    # update: true
+    packages:
+      - gcc-9
+      - g++-9
+      - build-essential
+      - python3
+      - python3-pip
+
+  homebrew:
+    update: false
+
+# ==============================================================================
+
+env:
+  global:
+    - OMP_NUM_THREADS=1
+    - CC=gcc-9
+    - CXX=g++-9
+
+os: linux
 language: python
-matrix:
-  include:
-  - os: linux
-    python: "2.7"
-    addons:
-      apt:
-        sources: ['ubuntu-toolchain-r-test']
-        packages: ['gcc-4.9', 'g++-4.9', 'gcc-7', 'g++-7']
-    env: CC=gcc-4.9 CXX=g++-4.9 PYTHON=2.7
-  - os: linux
-    python: "3.4"
-    addons:
-      apt:
-        sources: ['ubuntu-toolchain-r-test']
-        packages: ['gcc-4.9', 'g++-4.9', 'gcc-7', 'g++-7']
-    env: CC=gcc-4.9 CXX=g++-4.9 PYTHON=3.4
-  - os: linux
-    python: "3.5"
-    addons:
-      apt:
-        sources: ['ubuntu-toolchain-r-test']
-        packages: ['gcc-4.9', 'g++-4.9', 'gcc-7', 'g++-7']
-    env: CC=gcc-4.9 CXX=g++-4.9 PYTHON=3.5
-  - os: linux
-    python: "3.6"
-    addons:
-      apt:
-        sources: ['ubuntu-toolchain-r-test']
-        packages: ['gcc-4.9', 'g++-4.9', 'gcc-7', 'g++-7']
-    env: CC=gcc-4.9 CXX=g++-4.9 PYTHON=3.6
+
+python:
+  - 3.5
+  - 3.6
+  - 3.7
+  - 3.8
+  - 3.9
+
+jobs:
+  fast_finish: true
+  # Limit the number of builds to use less credits on Travis-CI
+  # include:
+  # - os: osx
+  #   osx_image: xcode12.2
+  #   language: shell
+  #   name: "Mac OS Python Homebrew"
+  #   env: CC=clang CXX=clang++
+  #   before_install:
+  #     - clang++ --version
+  # - os: windows
+  #   name: "Windows Python 3.8"
+  #   language: shell
+  #   before_install:
+  #     - unset CC CXX
+  #     - choco install python3 --version 3.8.8
+  #     - ln -s /c/Python38/python.exe /c/Python38/python3.exe
+  #     - python3 -m pip install --upgrade pip
+  #   env: PATH=/c/Python38:/c/Python38/Scripts:$PATH
+
+# ==============================================================================
+# Installation and testing
 
 install:
-  - if [ "${PYTHON:0:1}" = "3" ]; then export PY=3; fi
-  - pip$PY install --upgrade pip setuptools wheel
-  - pip$PY install --only-binary=numpy,scipy numpy scipy
-  - pip$PY install -r requirements.txt
-  - pip$PY install pytest-cov
-  - pip$PY install coveralls
-  - CC=g++-7 pip$PY install revkit
-  - if [ "${PYTHON:0:1}" = "3" ]; then pip$PY install dormouse; fi
-  - pip$PY install -e .
+  - env
+  - python3 -m pip install -U pip setuptools wheel
+  - python3 -m pip install -U pybind11 dormouse revkit flaky pytest-cov coveralls
+  - python3 -m pip install -r requirements.txt
+  - python3 -m pip install -ve .
 
 before_script:
   - "echo 'backend: Agg' > matplotlibrc"
 
-# command to run tests
-script: export OMP_NUM_THREADS=1 && pytest projectq --cov projectq -p no:warnings
+script:
+  - python3 -m pytest projectq --cov projectq -p no:warnings
 
 after_success:
   - coveralls
+
+# ==============================================================================

projectq/backends/_sim/_pysim.py

@@ -20,6 +20,11 @@
 
 import random
 import numpy as _np
+import os
+
+_USE_REFCHECK = True
+if 'TRAVIS' in os.environ:
+    _USE_REFCHECK = False
 
 
 class Simulator(object):
@@ -110,7 +115,7 @@ def allocate_qubit(self, ID):
         """
         self._map[ID] = self._num_qubits
         self._num_qubits += 1
-        self._state.resize(1 << self._num_qubits)
+        self._state.resize(1 << self._num_qubits, refcheck=_USE_REFCHECK)
 
     def get_classical_value(self, ID, tol=1.e-10):
         """

projectq/ops/_qubit_operator.py

@@ -159,7 +159,7 @@ def __init__(self, term=None, coefficient=1.):
         if term is None:
             return
         elif isinstance(term, tuple):
-            if term is ():
+            if term == ():
                 self.terms[()] = coefficient
             else:
                 # Test that input is a tuple of tuples and correct action