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More documentation for processing tests

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m-kuhn committed Feb 23, 2016
1 parent 8582f61 commit 467f3f0210a5b7e540699651dae73023e1c5bea9
Showing with 84 additions and 50 deletions.
  1. +84 −50 python/plugins/processing/tests/README.md
@@ -11,13 +11,11 @@ A basic test appears under the toplevel key `tests` and looks like this:
algorithm: qgis:polygoncentroids
params:
- type: vector
location: qgs
name: polys.shp
name: polys.gml
results:
- id: OUTPUT_LAYER
OUTPUT_LAYER:
type: vector
location: proc
name: polys_centroid.geojson
name: expected/polys_centroid.gml

How To
------
@@ -30,13 +28,11 @@ geometry types and good readability. Redirect output to
`python/plugins/processing/tests/testdata/expected`

When you have run the algorithm, go to "Processing" > "History" and find the
algorithm which you have just run. This looks like

processing.runalg("qgis:densifygeometries","/home/mku/dev/cpp/qgis/QGIS/tests/testdata/polys.shp",2,"/home/mku/dev/cpp/qgis/QGIS/python/plugins/processing/tests/testdata/polys_densify.geojson")
algorithm which you have just run. Right click the algorithm and click "Create test".
A new window will open with a text definition.

Open the file `python/plugins/processing/tests/testdata/algorithm_tests.yaml`,
copy an existing test block and adjust it to your needs based on the
information found in the history.
copy the text definition there.

The first string from the command goes to the key `algorithm`, the subsequent
ones to params and the last one(s) to results.
@@ -47,72 +43,110 @@ The above translates to
algorithm: qgis:densifygeometriesgivenaninterval
params:
- type: vector
location: qgs
name: polys.shp
name: polys.gml
- 2 # Interval
results:
- id: OUTPUT
OUTPUT:
type: vector
location: proc
name: expected/polys_densify.geojson
name: expected/polys_densify.gml

Params and results
------------------

Trivial type parameters
.......................
### Trivial type parameters

Params and results are specified as lists or dictionaries:

Params and results are specified as lists:
params:
INTERVAL: 5
INTERPOLATE: True
NAME: A processing test

or

params:
- 2
- string
- another param

As in the example above they can be plain variables.

Layer type parameters
.....................
### Layer type parameters

To specify layers you will have to specify
You will often need to specify layers as parameters. To specify a layer you will need to specify:

* the type
* `vector` or `raster`
* a location to allow using files from the shared qgis test data
* `qgs` will look for the file in the src/tests/testdata
* `proc` will look for the file in python/plugins/processing/tests/testdata
you should use this location for expected data.
* a name
* relative path like `expected/polys_centroid.geojson`
* relative path like `expected/polys_centroid.gml`

params:
- 2
- string
- type: vector
location: qgs
name: polys.shp
- another param
PAR: 2
STR: string
LAYER:
type: vector
name: polys.gml
OTHER: another param

Results
.......
### Results

Results have a special key `id` which is required because an algorithm can
produce multiple results. If you don't know the `id`, just start with `OUTPUT`
and run the test. You will be told if it was wrong and about the possible
values.
Results are specified very similar.

To deal with a certain tolerance for output values you can specify a
`compare` property for an output.
#### Basic vector files

It couldn't be more trivial

OUTPUT:
name: expected/qgis_intersection.gml
type: vector

#### Vector with tolerance

For a vector layer this means
Sometimes different platforms create slightly different results which are
still acceptable. In this case (but only then) you may also use additional
properties to define how exactly a layer is compared.

To deal with a certain tolerance for output values you can specify a
`compare` property for an output. The compare property can contain sub-properties
for `fields`. This contains information about how precisely a certain field is
compared (`precision`) or a field can even entirely be `skip`ed. There is a special
field name `__all__` which will apply a certain tolerance to all fields.
There is another property `geometry` which also accepts a `precision` which is
applied to each vertex.

OUTPUT:
type: vector
name: expected/abcd.geojson
compare:
fields:
__all__:
precision: 5 # compare to a precision of .00001 on all fields
A: skip # skip field A
geometry:
precision: 5 # compare coordinates with a precision of 5 digits
compare:
fields:
__all__:
precision: 5 # compare to a precision of .00001 on all fields
A: skip # skip field A
geometry:
precision: 5 # compare coordinates with a precision of 5 digits

#### Raster files

Raster files are compared with a hash checksum. This is calculated when you create
a test from the processing history.

OUTPUT:
type: rasterhash
hash: f1fedeb6782f9389cf43590d4c85ada9155ab61fef6dc285aaeb54d6

#### Files

You can compare the content of an ouptut file by an expected result reference file

OUTPUT_HTML_FILE:
name: expected/basic_statistics_string.html
type: file

Or you can use one or more regular expressions that will be [matched](https://docs.python.org/2/library/re.html#re.search) against the file
content

OUTPUT:
name: expected/gdal/layer_info.html
type: regex
rules:
- 'Extent: \(-1.000000, -3.000000\) - \(11.000000, 5.000000\)'
- 'Geometry: Line String'
- 'Feature Count: 6'

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