Merge commit '37324d63' into dev

python/.github/workflows/tests.yml

+# .github/workflows/tests.yml
+name: Tests
+on: push
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: [3.6, 3.7, 3.8, 3.9]
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies (pip and nox)
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install poetry nox
+    - name: Test with pytest (run with nox)
+      run: |
+        nox -p ${{ matrix.python-version }}
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v1
+      with:
+        fail_ci_if_error: false

python/.hgignore

@@ -9,5 +9,9 @@ _misc
 examples/*.ipynb
 src/visit-plugin
 *.npy
+*.pyc
+*.pyo
 *.wdat
-*.wtxt
\ No newline at end of file
+*.wtxt
+__pycache__/
+.ipynb_checkpoints/

python/.hgtags

+a390e129ef57168b34d866798e81570f2763a1d1 0.1.4

python/Makefile

+PANDOC_FLAGS = --toc --standalone
+
 all: README-PYPI.html README-test.html
 
 README-PYPI.html: README.md
@@ -6,7 +8,14 @@ README-PYPI.html: README.md
 README-test.html: README.md
 	pandoc -o $@ $< 
 
+%.html: %.md
+	pandoc $(PANDOC_FLAGS) $< -o $@  && open -g -a Safari $@
+	fswatch -e ".*\.html" -o . | while read num ; do pandoc $(PANDOC_FLAGS) $< -o $@ && open -g -a Safari $@; done
+
 .PHONY: all clean
 
 clean:
-	rm README*.html
+	-rm -rf .nox
+	-rm README*.html
+	-find . -type d -name "__pycache__" -exec rm -rf {} \;
+	-find . -type f -name "*.pyc" -delete

python/README.md

 W-data Format
 =============
+<!-- [Documentation Status](https://readthedocs.org/projects/wdata/badge/?version=latest)](https://wdata.readthedocs.io/en/latest/?badge=latest) -->
+[![Language grade: Python](https://img.shields.io/lgtm/grade/python/g/forbes-group/wdata.svg)](https://lgtm.com/projects/g/forbes-group/wdata/context:python)
+[![Tests](https://github.com/forbes-group/wdata/actions/workflows/tests.yml/badge.svg)](https://github.com/forbes-group/wdata/actions/workflows/tests.yml)
+[![codecov](https://codecov.io/gh/forbes-group/wdata/branch/branch/default/graph/badge.svg?token=U1GRP9B06D)](https://codecov.io/gh/forbes-group/wdata)
+[![Pypi](https://img.shields.io/pypi/v/wdata.svg)](https://pypi.python.org/pypi/wdata)
+[![pyversions](https://img.shields.io/pypi/pyversions/wdata.svg)](https://pypi.python.org/pypi/wdata)[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 
 This project contains tools for working with and manipulating the
 W-data format used for analyzing superfluid data generated by the [W-SLDA
@@ -25,7 +31,7 @@ Installation
 ------------
 
 ```bash
-pip install wdata
+python3 -m pip install wdata
 ```
 
 Basic Usage
@@ -39,28 +45,26 @@ currents (3-component real vectors) etc. on a regular lattice of shape
 The data is represented by two classes: 
 
 * `Var`: These are the data variables such as density, currents,
-  etc. with additional metadata (ee the `wdata.io.IVar` interface for
-  details):
-  
-  * `Var.name`: Name of variable as it will appear in VisIt for example.
-  * `Var.data`: The actual data as a NumPy array.
-  * `Var.description`: Description.
-  * `Var.filename`: The file where the data is stored on disk.
-  * `Var.unit`: Unit (mainly for use in VisIt... does not affect the data.)
-
-* `WData`: This represents a complete dataset.  Some relevant
-  attributes are (see `wdata.io.IWData` for details):
-  * `WData.infofile`: Location of the infofile (see below).  This is
-    where the metadata will be stored or loaded from.
-  * `WData.variables`: List of `Var` variables.
-  * `WData.xyz`: Abscissa `(x, y, z)` shaped so that they can be used
-    with broadcasting.  I.e. `r = np.sqrt(x**2+y**2+z**2)`.
-  * `WData.t`: Array of times.
-  * `WData.dim`: Dimension of dataset.  I.e. `dim==1` for 1D simulations,
-    `dim==3` for 3D simulations.
-  * `WData.aliases`: Dictionary of aliases.  Convenience for providing
-    alternative data access in VisIt.
-  * `WData.constants`: Dictionary of constants such as `kF`, `eF`.
+    etc. with additional metadata (ee the `wdata.io.IVar` interface for
+    details):
+    * `Var.name`: Name of variable as it will appear in VisIt for example.
+    * `Var.data`: The actual data as a NumPy array.
+    * `Var.description`: Description.
+    * `Var.filename`: The file where the data is stored on disk.
+    * `Var.unit`: Unit (mainly for use in VisIt... does not affect the data.)
+* `WData`: This represents a complete dataset.  Some relevant attributes are (see
+    `wdata.io.IWData` for details): 
+    * `WData.infofile`: Location of the infofile (see below).  This is where the
+        metadata will be stored or loaded from.
+    * `WData.variables`: List of `Var` variables.
+    * `WData.xyz`: Abscissa `(x, y, z)` shaped so that they can be used with
+        broadcasting.  I.e. `r = np.sqrt(x**2+y**2+z**2)`. 
+    * `WData.t`: Array of times.
+    * `WData.dim`: Dimension of dataset.  I.e. `dim==1` for 1D simulations, `dim==3` for
+        3D simulations. 
+    * `WData.aliases`: Dictionary of aliases.  Convenience for providing alternative
+        data access in VisIt.
+    * `WData.constants`: Dictionary of constants such as `kF`, `eF`.
 
 **Minimal Example**:
 
@@ -270,6 +274,16 @@ directly calls `__init__()`.  Keep this in mind when writing the docstrings.
 
 Changes
 =======
+## 0.1.5
+* Resolne issue #13: `WData` can now load read-only files.
+
+## 0.1.4
+* Resolve issue #8.  Vectors can have `Nv <= dim`.  Also, keep `Nxyz` info even if
+  `dim<3`: this is how plane-wave approximations are used sometimes.
+* Fixed many small bugs discovered by 100% coverage testing.
+* Pass-through `kwargs` from `io.WData.load()` etc. to constructor.
+* Added `check_data` flag to optionally disable testing of data.
+* Remove item-access.  Use attribute access instead: `data.x` or `getattr(data, 'x')`.
 
 ## 0.1.3
 * Address issue #4 for loading large datasets.  We now use memory mapped files.

python/docs/conf.py

@@ -13,7 +13,7 @@
 # import os
 # import sys
 # sys.path.insert(0, os.path.abspath('.'))
-
+import wdata
 
 # -- Project information -----------------------------------------------------
 
@@ -22,7 +22,7 @@ copyright = "2020, Michael McNeil Forbes"
 author = "Michael McNeil Forbes"
 
 # The full version, including alpha/beta/rc tags
-release = "0.1.3"
+release = wdata.__version__
 
 
 # -- General configuration ---------------------------------------------------

python/noxfile.py

@@ -13,3 +13,4 @@ def test(session: Session) -> None:
     # session.run("poetry", "shell", external=True)
     session.run("poetry", "install", external=True)
     session.run("poetry", "run", "pytest", external=True)
+    session.run("poetry", "run", "coverage", "xml", "--fail-under=0", external=True)

python/pyproject.toml

 [tool.poetry]
 name = "wdata"
-version = "0.1.3"
+version = "0.1.5"
 description = "W-Data format for superfluid dynamics and the W-SLDA Toolkit."
 authors = ["Michael McNeil Forbes <mforbes@alum.mit.edu>"]
 license = "MIT"
@@ -31,6 +31,7 @@ Sphinx = "^3.5.3"
 sphinxcontrib-zopeext = "^0.2.4"
 sphinx-autobuild = "^2020.9.1"
 sphinx-rtd-theme = "^0.5.0"
+readme-renderer = "^29.0"
 
 [tool.poetry.urls]
 "Bug Reports" = "https://hg.iscimath.org/forbes-group/wdata/issues"

python/src/wdata/__init__.py

-__version__ = "0.1.3"
+__version__ = "0.1.4"

python/tests/test_io.py

 """Test IO Routines"""
+import glob
 import os.path
+import stat
 import tempfile
 
 import numpy as np
@@ -21,6 +23,45 @@ def ext(request):
     yield request.param
 
 
+@pytest.fixture(params=[1, 2, 3])
+def dim(request):
+    yield request.param
+
+
+@pytest.fixture
+def infofile(data_dir, ext, dim):
+    """Reasonable datasets for testing."""
+    Nt = 4
+    Nxyz = (4, 8, 16)
+    dxyz = (0.1, 0.2, 0.3)
+
+    variables = [
+        io.Var(density=np.random.random((Nt,) + Nxyz[:dim])),
+        io.Var(current1=np.random.random((Nt, 1) + Nxyz[:dim])),
+        io.Var(current2=np.random.random((Nt, 2) + Nxyz[:dim])),
+        io.Var(current3=np.random.random((Nt, 3) + Nxyz[:dim])),
+    ]
+
+    data = io.WData(
+        prefix="tmp",
+        data_dir=data_dir,
+        ext=ext,
+        dim=dim,
+        Nxyz=Nxyz,
+        dxyz=dxyz,
+        variables=variables,
+        Nt=Nt,
+        aliases={"n": "density"},
+        constants=dict(hbar=1.23),
+    )
+
+    data.save()
+    infofile = data.infofile
+    del data
+
+    yield infofile
+
+
 class TestIO:
     def test_interfaces(self, data_dir):
         assert verifyClass(io.IVar, io.Var)
@@ -113,7 +154,8 @@ link       current_b  current_a
 # consts
 # tag       name       value
 const         eF         0.5
-const         kF           1"""
+const         kF           1
+"""
             )
 
         Nxyz = (24, 28, 32)
@@ -171,15 +213,27 @@ const         kF           1"""
         assert wdata.Nxyz == (24, 28, 32)
         assert wdata.xyz0 == (-24 / 2, -28 / 2, -32 / 2)
         assert wdata.dxyz == (1, 1, 1)
+        assert wdata.eF == 0.5
+        assert wdata.kF == 1.0
+        assert sorted(wdata) == [
+            "current_a",
+            "current_b",
+            "delta",
+            "density_a",
+            "density_b",
+            "eF",
+            "kF",
+        ]
 
         assert np.allclose(wdata.t, ts)
         assert np.allclose(wdata.t0, 0)
         assert np.allclose(wdata.dt, 1)
 
         density_a, delta_, current_a = wdata.variables
+        assert wdata.density_a is density_a.data
         assert density_a.name == "density_a"
         assert density_a.description == ""
-        assert density_a.ext == "wdat"
+        assert density_a.filename.endswith(".wdat")
         assert density_a.unit == "none"
         assert density_a.filename == f"{full_prefix}_density_a.wdat"
         assert density_a.descr == "<f8"
@@ -188,7 +242,7 @@ const         kF           1"""
 
         assert delta_.name == "delta"
         assert delta_.description == ""
-        assert delta_.ext == "wdat"
+        assert delta_.filename.endswith(".wdat")
         assert delta_.unit == "none"
         assert delta_.filename == f"{full_prefix}_delta.wdat"
         assert delta_.descr == "<c16"
@@ -197,7 +251,7 @@ const         kF           1"""
 
         assert current_a.name == "current_a"
         assert current_a.description == ""
-        assert current_a.ext == "wdat"
+        assert current_a.filename.endswith(".wdat")
         assert current_a.unit == "none"
         assert current_a.filename == f"{full_prefix}_current_a.wdat"
         assert current_a.descr == "<f8"
@@ -231,7 +285,8 @@ dt        1 # time interval between cycles
 # variables
 # tag           name     type      unit      format
 var        density       real      none        wdat
-var        current       vector    none        wdat
+var        current2      vector    none        wdat
+var        current3      vector    none        wdat
 """
             )
 
@@ -253,13 +308,23 @@ var        current       vector    none        wdat
         wx, wy = 2 * np.pi / Lxyz
         cos, sin = np.cos, np.sin
         density = np.array([cos(wx * t * x) * cos(wy * t * y) for t in ts])
-        current = np.array(
+        current2 = np.array(
             [
                 [cos(wx * t * x) * cos(wx * t * y), sin(wx * t * x) * sin(wx * t * y)]
                 for t in ts
             ]
         )
-        vars = dict(density=density, current=current)
+        current3 = np.array(
+            [
+                [
+                    cos(wx * t * x) * cos(wx * t * y),
+                    sin(wx * t * x) * sin(wx * t * y),
+                    0 * t * x * y,
+                ]
+                for t in ts
+            ]
+        )
+        vars = dict(density=density, current2=current2, current3=current3)
         for var in vars:
             with open(f"{full_prefix}_{var}.wdat", "wb") as f:
                 f.write(np.ascontiguousarray(vars[var]).tobytes())
@@ -272,30 +337,418 @@ var        current       vector    none        wdat
 
         assert all(np.allclose(_x, __x) for (_x, __x) in zip(wdata.xyz, xyz))
         assert wdata.dim == 2
-        assert wdata.Nxyz == (24, 28)
-        assert wdata.xyz0 == (-24 / 2, -28 / 2)
-        assert wdata.dxyz == (1, 1)
+        assert wdata.Nxyz[: wdata.dim] == (24, 28)
+        assert wdata.xyz0[: wdata.dim] == (-24 / 2, -28 / 2)
+        assert wdata.dxyz[: wdata.dim] == (1, 1)
 
         assert np.allclose(wdata.t, ts)
         assert np.allclose(wdata.t0, 0)
         assert np.allclose(wdata.dt, 1)
 
-        (density_, current_) = wdata.variables
+        (density_, current2_, current3_) = wdata.variables
 
         assert density_.name == "density"
         assert density_.description == ""
-        assert density_.ext == "wdat"
+        assert density_.filename.endswith(".wdat")
         assert density_.unit == "none"
         assert density_.filename == f"{full_prefix}_density.wdat"
         assert density_.descr == "<f8"
         assert not density_.vector
         assert np.allclose(density_.data, density)
 
-        assert current_.name == "current"
-        assert current_.description == ""
-        assert current_.ext == "wdat"
-        assert current_.unit == "none"
-        assert current_.filename == f"{full_prefix}_current.wdat"
-        assert current_.descr == "<f8"
-        assert current_.vector
-        assert np.allclose(current_.data, current)
+        assert current2_.name == "current2"
+        assert current2_.description == ""
+        assert current2_.filename.endswith(".wdat")
+        assert current2_.unit == "none"
+        assert current2_.filename == f"{full_prefix}_current2.wdat"
+        assert current2_.descr == "<f8"
+        assert current2_.vector
+        assert np.allclose(current2_.data, current2)
+
+        assert current3_.name == "current3"
+        assert current3_.description == ""
+        assert current3_.filename.endswith(".wdat")
+        assert current3_.unit == "none"
+        assert current3_.filename == f"{full_prefix}_current3.wdat"
+        assert current3_.descr == "<f8"
+        assert current3_.vector
+        assert np.allclose(current3_.data, current3)
+
+    @pytest.mark.filterwarnings("error")
+    def test_issue5(self, data_dir, ext):
+        x = np.array([1, 2, 4, 5])
+        y = np.array([1, 2, 3, 4, 5])
+        xyz = [x[:, np.newaxis], y[np.newaxis, :]]
+        t = [0]
+        prefix = "tmp"
+        full_prefix = os.path.join(data_dir, prefix)
+
+        data = io.WData(prefix=prefix, data_dir=data_dir, xyz=xyz, t=t, ext=ext)
+        assert np.isnan(data.dt)
+        assert np.isnan(data.dxyz[0])
+        assert np.allclose(1.0, data.dxyz[1])
+        data.save()
+
+        infofile = f"{full_prefix}.wtxt"
+        with open(infofile, "r") as f:
+            found = set()
+            for line in f.readlines():
+                if line.startswith("DX"):
+                    found.add("DX")
+                    assert line == "DX         varying    # Spacing in X direction\n"
+                if line.startswith("DY"):
+                    found.add("DY")
+                    assert line == "DY             1.0    #        ... Y ...\n"
+                if line.startswith("dt"):
+                    found.add("dt")
+                    assert (
+                        line == "dt         varying    # Time interval between frames\n"
+                    )
+            assert len(found) == 3
+
+        wdata = io.WData.load(infofile=infofile)
+
+        assert np.isnan(wdata.dt)
+        assert np.isnan(wdata.dxyz[0])
+        assert np.allclose(1.0, wdata.dxyz[1])
+
+    def test_metadata(self, data_dir, ext):
+        x = np.array([1, 2, 3, 5])
+        y = np.array([1, 2, 3, 4, 5])
+        xyz = [x[:, np.newaxis], y[np.newaxis, :]]
+        t = [0, 1.2]
+        prefix = "tmp"
+        full_prefix = os.path.join(data_dir, prefix)
+
+        Nxyz = sum(xyz).shape
+        x = io.Var(x=np.ones((len(t),) + Nxyz, dtype=complex))
+        data = io.WData(
+            prefix=prefix,
+            data_dir=data_dir,
+            xyz=xyz,
+            t=t,
+            ext=ext,
+            variables=[x],
+            aliases={"y": "x"},
+            constants=dict(hbar=1.23),
+        )
+
+        data.save()
+
+        infofile = f"{full_prefix}.wtxt"
+        with open(infofile, "r") as f:
+            found = set()
+            for line in f.readlines():
+                if line.startswith("DX"):
+                    found.add("DX")
+                    assert line == "DX         varying    # Spacing in X direction\n"
+                if line.startswith("DY"):
+                    found.add("DY")
+                    assert line == "DY             1.0    #        ... Y ...\n"
+                if line.startswith("dt"):
+                    found.add("dt")
+                    assert (
+                        line == "dt             1.2    # Time interval between frames\n"
+                    )
+                if line.startswith("var"):
+                    found.add("var")
+                    assert (
+                        line
+                        == f"var         x    complex    none      {ext:>4}    # x\n"
+                    )
+                if line.startswith("link"):
+                    found.add("link")
+                    assert line == "link        y          x\n"
+                if line.startswith("const"):
+                    found.add("const")
+                    assert line == "const    hbar     1.23"
+            assert len(found) == 6
+
+    def test_missing_prefix(self, data_dir):
+        prefix = "test"
+        full_prefix = os.path.join(data_dir, f"{prefix}")
+        info_contents = """
+# Generated by td-wslda-2d [12/13/20-16:51:30]
+
+NX        4 # lattice
+NY        5 # lattice
+DX        1 # spacing
+DY        1 # spacing
+datadim   2 # dimension of block size: 1=NX, 2=NX*NY, 3=NX*NY*NZ
+cycles    3 # number of cycles (measurements)
+t0        0 # time value for the first cycle
+dt        1 # time interval between cycles
+
+# variables
+# tag           name     type      unit      format
+var        density       real      none         npy
+"""
+        density = np.ones((3, 4, 5), dtype=float)
+        filename = f"{full_prefix}_density.npy"
+        np.save(filename, density)
+
+        for info_ext in ["wtxt", "custom"]:
+            infofile = f"{full_prefix}.{info_ext}"
+            with open(infofile, "w") as f:
+                f.write(info_contents)
+            data = io.WData.load(infofile)
+            assert data.prefix == prefix
+
+    def test_save(self, infofile):
+        data = io.WData.load(infofile)
+        data_dir = os.path.dirname(infofile)
+        new_data_dir = os.path.join(data_dir, "new")
+        data.data_dir = new_data_dir
+        data.save(force=True)
+
+    def test_dts(self):
+        data = io.WData(Nxyz=(4, 5, 6), t=[1, 2, 3, 4, 5])
+        assert data.dt == 1
+        data = io.WData(Nxyz=(4, 5, 6), t=[1, 2, 3, 5])
+        assert np.isnan(data.dt)
+
+    def test__get_ext(self, ext):
+        x = io.Var(x=np.zeros((1, 4, 5)), filename=f"x.{ext}")
+
+        data = io.WData(Nxyz=x.shape[1:], variables=[x])
+        info = data.get_metadata()
+        assert ext in info
+
+    def test_readonly(self, data_dir, ext):
+        """Issue 13: fail on read-only file systems."""
+        Nxyz = (4, 8)
+        dxyz = (0.1, 0.2)
+        prefix = "tmp"
+        full_prefix = os.path.join(data_dir, prefix)
+
+        data = io.WData(
+            prefix=prefix, data_dir=data_dir, Nxyz=Nxyz, dxyz=dxyz, Nt=1, ext=ext
+        )
+
+        xyz = data.xyz
+
+        np.random.seed(2)
+
+        psi = np.random.random(Nxyz + (2,)) - 0.5
+        psi = psi.view(dtype=complex)[..., 0]
+        assert psi.shape == Nxyz
+
+        psis = [psi]
+        densities = [abs(psi) ** 2]
+
+        data = io.WData(
+            data_dir=data_dir,
+            xyz=xyz,
+            variables=[io.Var(density=densities), io.Var(delta=psis)],
+            ext=ext,
+        )
+        data.save()
+
+        # Make files read-only
+        for (dirpath, dirnames, filenames) in os.walk(data_dir):
+            for file in filenames:
+                os.chmod(os.path.join(dirpath, file), stat.S_IRUSR)
+
+        # Try loading
+        res = io.WData.load(full_prefix=full_prefix)
+        assert np.allclose(res.delta, psi)
+        assert np.allclose(res.density, densities)
+
+
+class TestVar:
+    def test_descr(self):
+        """Test setting descr."""
+        v = io.Var(x=np.ones(10), descr=complex)
+        assert v.data.dtype == complex
+        assert io.WData._get_type(v) == "abscissa"
+
+        v = io.Var(x=np.ones((3, 10), dtype="<f4"))
+        assert io.WData._get_type(v) == "<f4"
+        assert io.WData._get_descr("<f4") == "<f4"
+
+    def test_set(self):
+        """Test setting attributes."""
+        v = io.Var(x=np.ones(10))
+        assert v.data.dtype == float
+        assert v.shape == (10,)
+
+        v.data = 1j * np.arange(12)
+        assert v.data.dtype == complex
+        assert v.shape == (12,)
+
+        v.shape = (3, 4)
+        assert v.data.shape == (3, 4)
+
+        with pytest.raises(ValueError) as excinfo:
+            v.shape = (3, 5)
+        assert (
+            str(excinfo.value)
+            == "Property shape=(3, 5) incompatible with data.shape=(3, 4)"
+        )
+
+    def test_write_data(self, data_dir):
+        filename = os.path.join(data_dir, "tmp.wdat")
+
+        v = io.Var(x=np.arange(10))
+        with pytest.raises(ValueError) as excinfo:
+            v.write_data()
+        assert str(excinfo.value) == "No filename specified in Var."
+
+        v.write_data(filename)
+        assert os.path.exists(f"{filename}")
+
+        with pytest.raises(IOError) as excinfo:
+            v.write_data(filename)
+        assert str(excinfo.value) == f"File '{filename}' already exists!"
+
+        with pytest.raises(NotImplementedError) as excinfo:
+            v.write_data(filename="x.unknown")
+        assert str(excinfo.value) == "Unsupported extension for 'x.unknown'"
+
+        v = io.Var(name="x", filename=filename)
+        with pytest.raises(ValueError) as excinfo:
+            v.write_data()
+        assert str(excinfo.value) == "Missing data for 'x'!"
+
+    def test_getattr(self):
+        data = io.WData(Nxyz=(4, 5), t=[1, 2])
+        with pytest.raises(AttributeError) as excinfo:
+            data.unknown
+        assert str(excinfo.value) == "'WData' object has no attribute 'unknown'"
+
+
+class TestErrors:
+    """Test coverage and errors."""
+
+    def test_var_errors(self):
+        with pytest.raises(ValueError) as excinfo:
+            io.Var()
+        assert str(excinfo.value) == "Must provide `name` or data as a kwarg: got {}"
+
+        with pytest.raises(ValueError) as excinfo:
+            io.Var(data=np.ones((4, 4)))
+        assert str(excinfo.value) == "Got data but no name."
+
+        v = io.Var(name="x", filename="tmp.unknown")
+        with pytest.raises(NotImplementedError) as excinfo:
+            v.load_data()
+        assert str(excinfo.value) == "Data format of 'tmp.unknown' not supported."
+
+    def test_wdata_errors(self):
+        with pytest.raises(ValueError) as excinfo:
+            io.WData()
+        assert str(excinfo.value) == "Must provide one of xyz or Nxyz"
+
+        with pytest.raises(ValueError) as excinfo:
+            io.WData(Nxyz=(4, 5))
+        assert str(excinfo.value) == "Must provide t, Nt, or a variable with data"
+
+        with pytest.raises(ValueError) as excinfo:
+            io.WData(Nxyz=(3, 4, 5), Nt=1)
+        assert str(excinfo.value) == "First dimension of Nxyz==(3, 4, 5) must be > 3."
+
+        with pytest.raises(ValueError) as excinfo:
+            x = io.Var(x=np.zeros((2, 4, 5)))
+            io.WData(Nxyz=(4, 5), Nt=1, variables=[x])
+        assert (
+            str(excinfo.value)
+            == "Variable 'x' has incompatible Nt=1: data.shape[0] = 2"
+        )
+
+        with pytest.raises(ValueError) as excinfo:
+            x = io.Var(x=np.zeros((2, 4)))
+            io.WData(Nxyz=(5,), Nt=2, variables=[x])
+        assert (
+            str(excinfo.value)
+            == "Variable 'x' has incompatible Nxyz=(5,): data.shape[-1:] = (4,)"
+        )
+
+        with pytest.raises(ValueError) as excinfo:
+            x = io.Var(x=np.zeros((2, 4, 4, 6)))
+            io.WData(Nxyz=(4, 6), dim=2, Nt=2, variables=[x])
+        assert (
+            str(excinfo.value)
+            == "Variable 'x' has incompatible dim=2: data.shape = (2, 4, 4, 6)"
+        )
+
+    @pytest.mark.filterwarnings("error")
+    def test_getitem(self):
+        x = io.Var(x=np.zeros((2, 4, 5)))
+        data = io.WData(Nxyz=(4, 5), t=[1, 2], variables=[x], constants=dict(x=3))
+        with pytest.warns(
+            UserWarning, match="Variable x hides constant of the same name"
+        ):
+            data.x
+
+        data = io.WData(Nxyz=(4, 5), t=[1, 2], variables=[x], constants=dict(y=3))
+        with pytest.raises(AttributeError) as excinfo:
+            data.q
+        assert str(excinfo.value) == "'WData' object has no attribute 'q'"
+
+        data.keys()
+
+    def test__dir__(self):
+        x = io.Var(x=np.zeros((2, 4, 5)))
+        data = io.WData(Nxyz=(4, 5), t=[1, 2], variables=[x], constants=dict(x=3))
+        assert dir(data) == ["x"]
+
+    def test_load_errors(self, data_dir):
+        with pytest.raises(ValueError) as excinfo:
+            io.WData.load()
+        assert str(excinfo.value) == "Must provide either infofile or full_prefix."
+
+        with pytest.raises(ValueError) as excinfo:
+            io.WData.load(infofile="info", full_prefix="/")
+        assert str(excinfo.value) == "Got both infofile=info and full_prefix=/."
+
+        with pytest.raises(NotImplementedError) as excinfo:
+            io.WData.load(full_prefix=data_dir)
+
+    def test_save_errors(self, infofile):
+        with pytest.raises(NotImplementedError) as excinfo:
+            data = io.load_wdata(infofile)
+
+        data = io.load_wdata(infofile=infofile)
+
+        with pytest.raises(IOError) as excinfo:
+            data.save()
+        assert str(excinfo.value) == f"File '{infofile}' already exists!"
+
+        data_dir = os.path.dirname(infofile)
+        new_data_dir = os.path.join(data_dir, "new")
+        data.data_dir = new_data_dir
+        with pytest.raises(IOError) as excinfo:
+            data.save()
+        assert (
+            str(excinfo.value) == f"Directory data_dir={new_data_dir} does not exist."
+        )
+
+    def test_invalid_vector(self, infofile):
+        data = io.WData.load(infofile)
+
+        if data.dim == 1:
+            for var in data.variables:
+                if var.name == "current1":
+                    break
+
+            if var.filename.endswith(".wdat"):
+                # Break data by changing size... make sure we copy it first though since
+                # we are using mem-mapped files!
+                A = np.array(var.data.ravel()[:-1])
+                filename = var.filename
+                assert os.path.exists(filename)
+                with open(filename, "wb") as fd:
+                    fd.write(A.tobytes())
+
+                _data = np.memmap(filename, dtype=np.dtype(A.dtype))
+                assert _data.shape == A.shape
+
+                # This should work...
+                data_ = io.WData.load(infofile, check_data=False)
+
+                # but this should fail
+                with pytest.raises(ValueError) as excinfo:
+                    data_.current1
+                msg = str(excinfo.value)
+                assert "Shape of data" in msg
+                assert "Nv=0.9375 must be an integer." in msg