Added a test for missing output.layers

tests/test_plot/test_yaml_errors.py

@@ -9,9 +9,11 @@ Tests various errors in the config file
   - Incorrect name
   - Inner.1, but no inner layers
   - Inner_1 (malformed)
-- No output.name
-- No output.type
-- No output.options
+- No output:
+  - name
+  - type
+  - options
+  - layers
 
 For debug information use:
 pytest-3 --log-cli-level debug
@@ -96,3 +98,10 @@ def test_no_options():
     ctx.run(EXIT_BAD_CONFIG)
     assert ctx.search_err("Output 'PDF' needs options")
     ctx.clean_up()
+
+
+def test_no_layers():
+    ctx = context.TestContext('ErrorNoLayers', '3Rs', 'error_no_layers', None)
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("You must specify the layers for `PDF`")
+    ctx.clean_up()

tests/yaml_samples/error_no_layers.kiplot.yaml

@@ -0,0 +1,25 @@
+kiplot:
+  version: 1
+
+outputs:
+  - name: PDF
+    comment: "PDF files"
+    type: pdf
+    dir: PDF
+    options:
+      exclude_edge_layer: false
+      exclude_pads_from_silkscreen: false
+      use_aux_axis_as_origin: false
+      plot_sheet_reference: false
+      plot_footprint_refs: true
+      plot_footprint_values: true
+      force_plot_invisible_refs_vals: false
+      tent_vias: true
+      check_zone_fills: true
+
+      # PDF options
+      drill_marks: small
+      mirror_plot: false
+      negative_plot: false
+      line_width: 0.01
+