Fix import errors without dev dependencies (#214)

* add ci test for import without dev dependencies

* fix tensorflow import error

.github/workflows/ci_test.yml

@@ -54,3 +54,34 @@ jobs:
 
       - name: Test Examples
         run: bash scripts/test-examples.sh
+
+  test-import:
+    name: Test Import without Dev Dependencies
+    if: ${{ !contains(github.event.pull_request.title, 'WIP') }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # python-version: [3.9]
+        python-version: [3.7, 3.8, 3.9]
+    steps:
+      - name: Check out the code
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 1
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install Poetry
+        uses: snok/install-poetry@v1.1.1
+        with:
+          version: 1.1.4
+
+      - name: Install Dependencies
+        run: |
+          poetry config virtualenvs.create false
+          poetry install --no-dev
+
+      - name: Import Elegy
+        run: python -c "import elegy"

elegy/model/model_core.py

@@ -10,16 +10,17 @@
 import jax.numpy as jnp
 import numpy as np
 import treex as tx
-from jax.experimental import jax2tf
 
 from elegy import types, utils
 
 from . import utils as model_utils
 
 try:
     import tensorflow as tf
+    from jax.experimental import jax2tf
 except ImportError:
     tf = None
+    jax2tf = None
 
 A = tp.TypeVar("A")
 M = tp.TypeVar("M", bound="ModelCore")
@@ -727,6 +728,8 @@ def saved_model(
         if model_utils.convert_and_save_model is None:
             raise ImportError(f"Could not import tensorflow.")
 
+        assert jax2tf is not None
+
         if isinstance(batch_size, int):
             batch_size = [batch_size]