diff --git a/kiplot/config_reader.py b/kiplot/config_reader.py
index 2335a1a4..b2341023 100644
--- a/kiplot/config_reader.py
+++ b/kiplot/config_reader.py
@@ -115,29 +115,24 @@ class CfgYamlReader(object):
 
     def _parse_layers(self, layers_to_parse):
         # Check we have a list of layers
-        if not layers_to_parse:
-            raise KiPlotConfigurationError("Missing `layers` definition")
         if not isinstance(layers_to_parse, list):
             raise KiPlotConfigurationError("`layers` must be a list")
         # Parse the elements
         layers = []
         for l in layers_to_parse:
-            # Check they are dictionaries
-            if not isinstance(l, dict):
-                raise KiPlotConfigurationError("Malformed `layer` entry ({})".format(l))
             # Extract the attributes
             layer = None
             description = 'no desc'
             suffix = ''
             for k, v in l.items():
                 if k == 'layer':
-                    layer = v
+                    layer = str(v)
                 elif k == 'description':
-                    description = v
+                    description = str(v)
                 elif k == 'suffix':
-                    suffix = v
+                    suffix = str(v)
                 else:
-                    raise KiPlotConfigurationError("Unknown {} attribute for `layer`".format(v))
+                    raise KiPlotConfigurationError("Unknown `{}` attribute for `layer`".format(k))
             # Check we got the layer name
             if layer is None:
                 raise KiPlotConfigurationError("Missing `layer` attribute for layer entry ({})".format(l))
@@ -217,7 +212,7 @@ class CfgYamlReader(object):
                 logger.debug("Adding DRC/ERC filter '{}','{}','{}'".format(comment, number, regex))
                 if parsed is None:
                     parsed = ''
-                if not comment:
+                if comment:
                     parsed += '# '+comment+'\n'
                 parsed += '{},{}\n'.format(number, regex)
             else:
@@ -268,7 +263,7 @@ class CfgYamlReader(object):
                 else:
                     config_error("`outputs` must be a list")
             else:
-                logger.warning('Skipping unknown `{}` section in config.'.format(k))
+                config_error('Unknown section `{}` in config.'.format(k))
         if version is None:
             config_error("YAML config needs `kiplot.version`.")
         return outputs
diff --git a/tests/board_samples/good-project.kicad_pcb b/tests/board_samples/good-project.kicad_pcb
new file mode 100644
index 00000000..01baad5f
--- /dev/null
+++ b/tests/board_samples/good-project.kicad_pcb
@@ -0,0 +1,295 @@
+(kicad_pcb (version 20171130) (host pcbnew 5.1.5+dfsg1-2~bpo10+1)
+
+  (general
+    (thickness 1.6)
+    (drawings 6)
+    (tracks 20)
+    (zones 0)
+    (modules 4)
+    (nets 4)
+  )
+
+  (page A4)
+  (layers
+    (0 F.Cu signal)
+    (1 GND.Cu signal)
+    (2 Signal1.Cu signal)
+    (3 Signal2.Cu signal)
+    (4 Power.Cu signal)
+    (31 B.Cu signal)
+    (32 B.Adhes user)
+    (33 F.Adhes user)
+    (34 B.Paste user)
+    (35 F.Paste user)
+    (36 B.SilkS user)
+    (37 F.SilkS user)
+    (38 B.Mask user)
+    (39 F.Mask user)
+    (40 Dwgs.User user)
+    (41 Cmts.User user)
+    (42 Eco1.User user)
+    (43 Eco2.User user)
+    (44 Edge.Cuts user)
+    (45 Margin user)
+    (46 B.CrtYd user)
+    (47 F.CrtYd user)
+    (48 B.Fab user)
+    (49 F.Fab user)
+  )
+
+  (setup
+    (last_trace_width 0.25)
+    (trace_clearance 0.2)
+    (zone_clearance 0.508)
+    (zone_45_only no)
+    (trace_min 0.2)
+    (via_size 0.8)
+    (via_drill 0.4)
+    (via_min_size 0.4)
+    (via_min_drill 0.3)
+    (uvia_size 0.3)
+    (uvia_drill 0.1)
+    (uvias_allowed no)
+    (uvia_min_size 0.2)
+    (uvia_min_drill 0.1)
+    (edge_width 0.05)
+    (segment_width 0.2)
+    (pcb_text_width 0.3)
+    (pcb_text_size 1.5 1.5)
+    (mod_edge_width 0.12)
+    (mod_text_size 1 1)
+    (mod_text_width 0.15)
+    (pad_size 1.524 1.524)
+    (pad_drill 0.762)
+    (pad_to_mask_clearance 0.051)
+    (solder_mask_min_width 0.25)
+    (aux_axis_origin 0 0)
+    (visible_elements FFFFFF7F)
+    (pcbplotparams
+      (layerselection 0x010fc_ffffffff)
+      (usegerberextensions false)
+      (usegerberattributes false)
+      (usegerberadvancedattributes false)
+      (creategerberjobfile false)
+      (excludeedgelayer true)
+      (linewidth 0.100000)
+      (plotframeref false)
+      (viasonmask false)
+      (mode 1)
+      (useauxorigin false)
+      (hpglpennumber 1)
+      (hpglpenspeed 20)
+      (hpglpendiameter 15.000000)
+      (psnegative false)
+      (psa4output false)
+      (plotreference true)
+      (plotvalue true)
+      (plotinvisibletext false)
+      (padsonsilk false)
+      (subtractmaskfromsilk false)
+      (outputformat 1)
+      (mirror false)
+      (drillshape 1)
+      (scaleselection 1)
+      (outputdirectory ""))
+  )
+
+  (net 0 "")
+  (net 1 /Power/VCC)
+  (net 2 GND)
+  (net 3 "Net-(C2-Pad1)")
+
+  (net_class Default "This is the default net class."
+    (clearance 0.2)
+    (trace_width 0.25)
+    (via_dia 0.8)
+    (via_drill 0.4)
+    (uvia_dia 0.3)
+    (uvia_drill 0.1)
+    (add_net /Power/VCC)
+    (add_net GND)
+    (add_net "Net-(C2-Pad1)")
+  )
+
+  (module Capacitor_SMD:C_0402_1005Metric (layer F.Cu) (tedit 5B301BBE) (tstamp 5CA72801)
+    (at 164.775001 80.505001 90)
+    (descr "Capacitor SMD 0402 (1005 Metric), square (rectangular) end terminal, IPC_7351 nominal, (Body size source: http://www.tortai-tech.com/upload/download/2011102023233369053.pdf), generated with kicad-footprint-generator")
+    (tags capacitor)
+    (path /5CA71704/5CA745A6)
+    (attr smd)
+    (fp_text reference C1 (at 0 -1.17 90) (layer F.SilkS)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (fp_text value C (at 0 1.17 90) (layer F.Fab)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (fp_line (start -0.5 0.25) (end -0.5 -0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start -0.5 -0.25) (end 0.5 -0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start 0.5 -0.25) (end 0.5 0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start 0.5 0.25) (end -0.5 0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start -0.93 0.47) (end -0.93 -0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start -0.93 -0.47) (end 0.93 -0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 0.93 -0.47) (end 0.93 0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 0.93 0.47) (end -0.93 0.47) (layer F.CrtYd) (width 0.05))
+    (fp_text user %R (at 0 0 90) (layer F.Fab)
+      (effects (font (size 0.25 0.25) (thickness 0.04)))
+    )
+    (pad 1 smd roundrect (at -0.485 0 90) (size 0.59 0.64) (layers F.Cu F.Paste F.Mask) (roundrect_rratio 0.25)
+      (net 1 /Power/VCC))
+    (pad 2 smd roundrect (at 0.485 0 90) (size 0.59 0.64) (layers F.Cu F.Paste F.Mask) (roundrect_rratio 0.25)
+      (net 2 GND))
+    (model ${KIPRJMOD}/3D/C_0402_1005Metric.wrl
+      (at (xyz 0 0 0))
+      (scale (xyz 1 1 1))
+      (rotate (xyz 0 0 0))
+    )
+  )
+
+  (module Capacitor_SMD:C_0402_1005Metric (layer F.Cu) (tedit 5B301BBE) (tstamp 5CA72810)
+    (at 170.18 80.020001 90)
+    (descr "Capacitor SMD 0402 (1005 Metric), square (rectangular) end terminal, IPC_7351 nominal, (Body size source: http://www.tortai-tech.com/upload/download/2011102023233369053.pdf), generated with kicad-footprint-generator")
+    (tags capacitor)
+    (path /5CA75BC1/5CA76352)
+    (attr smd)
+    (fp_text reference C2 (at 0 -1.17 90) (layer F.SilkS)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (fp_text value C (at 0 1.17 90) (layer F.Fab)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (fp_text user %R (at 0 0 90) (layer F.Fab)
+      (effects (font (size 0.25 0.25) (thickness 0.04)))
+    )
+    (fp_line (start 0.93 0.47) (end -0.93 0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 0.93 -0.47) (end 0.93 0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start -0.93 -0.47) (end 0.93 -0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start -0.93 0.47) (end -0.93 -0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 0.5 0.25) (end -0.5 0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start 0.5 -0.25) (end 0.5 0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start -0.5 -0.25) (end 0.5 -0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start -0.5 0.25) (end -0.5 -0.25) (layer F.Fab) (width 0.1))
+    (pad 2 smd roundrect (at 0.485 0 90) (size 0.59 0.64) (layers F.Cu F.Paste F.Mask) (roundrect_rratio 0.25)
+      (net 2 GND))
+    (pad 1 smd roundrect (at -0.485 0 90) (size 0.59 0.64) (layers F.Cu F.Paste F.Mask) (roundrect_rratio 0.25)
+      (net 3 "Net-(C2-Pad1)"))
+    (model ${KIPRJMOD}/3D/C_0402_1005Metric.wrl
+      (at (xyz 0 0 0))
+      (scale (xyz 1 1 1))
+      (rotate (xyz 0 0 0))
+    )
+  )
+
+  (module Connector_JST:JST_JWPF_B02B-JWPF-SK-R_1x02_P2.00mm_Vertical (layer F.Cu) (tedit 5B772B89) (tstamp 5CA7282D)
+    (at 154.94 80.01)
+    (descr "JST JWPF series connector, B02B-JWPF-SK-R (http://www.jst-mfg.com/product/pdf/eng/eJWPF1.pdf), generated with kicad-footprint-generator")
+    (tags "connector JST JWPF side entry")
+    (path /5CA71704/5CA714F2)
+    (fp_text reference P1 (at -1.35 -3.7) (layer F.SilkS)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (fp_text value CONN_01X02 (at -1.35 5.7) (layer F.Fab)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (fp_arc (start 1.7 -1.5) (end 1.7 -2.5) (angle 90) (layer F.Fab) (width 0.1))
+    (fp_arc (start 1.7 3.5) (end 2.7 3.5) (angle 90) (layer F.Fab) (width 0.1))
+    (fp_arc (start 1.81 -1.61) (end 1.81 -2.61) (angle 90) (layer F.SilkS) (width 0.12))
+    (fp_arc (start 1.81 3.61) (end 2.81 3.61) (angle 90) (layer F.SilkS) (width 0.12))
+    (fp_line (start -5.9 -3) (end -5.9 5) (layer F.CrtYd) (width 0.05))
+    (fp_line (start -5.9 5) (end 3.2 5) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 3.2 5) (end 3.2 -3) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 3.2 -3) (end -5.9 -3) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 1.7 -2.5) (end -5.4 -2.5) (layer F.Fab) (width 0.1))
+    (fp_line (start -5.4 -2.5) (end -5.4 4.5) (layer F.Fab) (width 0.1))
+    (fp_line (start -5.4 4.5) (end 1.7 4.5) (layer F.Fab) (width 0.1))
+    (fp_line (start 2.7 -1.5) (end 2.7 3.5) (layer F.Fab) (width 0.1))
+    (fp_line (start 1.81 -2.61) (end -5.51 -2.61) (layer F.SilkS) (width 0.12))
+    (fp_line (start -5.51 -2.61) (end -5.51 4.61) (layer F.SilkS) (width 0.12))
+    (fp_line (start -5.51 4.61) (end 1.81 4.61) (layer F.SilkS) (width 0.12))
+    (fp_line (start 2.81 -1.61) (end 2.81 3.61) (layer F.SilkS) (width 0.12))
+    (fp_line (start -5.75 -1.35) (end -5.75 -2.85) (layer F.SilkS) (width 0.12))
+    (fp_line (start -5.75 -2.85) (end -4.25 -2.85) (layer F.SilkS) (width 0.12))
+    (fp_line (start -0.375 -1.9) (end 0.375 -1.9) (layer F.Fab) (width 0.1))
+    (fp_line (start 0.375 -1.9) (end 0 -1.15) (layer F.Fab) (width 0.1))
+    (fp_line (start 0 -1.15) (end -0.375 -1.9) (layer F.Fab) (width 0.1))
+    (fp_text user %R (at -4.7 1 90) (layer F.Fab)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (pad 1 thru_hole roundrect (at 0 0) (size 2 1.3) (drill 1) (layers *.Cu *.Mask) (roundrect_rratio 0.192308)
+      (net 2 GND))
+    (pad 2 thru_hole oval (at 0 2) (size 2 1.3) (drill 1) (layers *.Cu *.Mask)
+      (net 1 /Power/VCC))
+    (pad "" np_thru_hole circle (at -1.5 4.05) (size 1.15 1.15) (drill 1.15) (layers *.Cu *.Mask))
+    (model ${KIPRJMOD}/3D/B02B-JWPF-SK-R.step
+      (offset (xyz -3.2 -4.5 -8))
+      (scale (xyz 1 1 1))
+      (rotate (xyz 0 0 -90))
+    )
+  )
+
+  (module Resistor_SMD:R_0402_1005Metric (layer F.Cu) (tedit 5B301BBD) (tstamp 5CA7283C)
+    (at 167.64 83.82)
+    (descr "Resistor SMD 0402 (1005 Metric), square (rectangular) end terminal, IPC_7351 nominal, (Body size source: http://www.tortai-tech.com/upload/download/2011102023233369053.pdf), generated with kicad-footprint-generator")
+    (tags resistor)
+    (path /5CA75BC1/5CA75C86)
+    (attr smd)
+    (fp_text reference R1 (at 0 -1.17) (layer F.SilkS)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (fp_text value R (at 0 1.17) (layer F.Fab)
+      (effects (font (size 1 1) (thickness 0.15)))
+    )
+    (fp_line (start -0.5 0.25) (end -0.5 -0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start -0.5 -0.25) (end 0.5 -0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start 0.5 -0.25) (end 0.5 0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start 0.5 0.25) (end -0.5 0.25) (layer F.Fab) (width 0.1))
+    (fp_line (start -0.93 0.47) (end -0.93 -0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start -0.93 -0.47) (end 0.93 -0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 0.93 -0.47) (end 0.93 0.47) (layer F.CrtYd) (width 0.05))
+    (fp_line (start 0.93 0.47) (end -0.93 0.47) (layer F.CrtYd) (width 0.05))
+    (fp_text user %R (at 0 0) (layer F.Fab)
+      (effects (font (size 0.25 0.25) (thickness 0.04)))
+    )
+    (pad 1 smd roundrect (at -0.485 0) (size 0.59 0.64) (layers F.Cu F.Paste F.Mask) (roundrect_rratio 0.25)
+      (net 1 /Power/VCC))
+    (pad 2 smd roundrect (at 0.485 0) (size 0.59 0.64) (layers F.Cu F.Paste F.Mask) (roundrect_rratio 0.25)
+      (net 3 "Net-(C2-Pad1)"))
+    (model ${KIPRJMOD}/3D/R_0402_1005Metric.wrl
+      (at (xyz 0 0 0))
+      (scale (xyz 1 1 1))
+      (rotate (xyz 0 0 0))
+    )
+  )
+
+  (gr_text "Text in Cmts.User" (at 149 93) (layer Cmts.User)
+    (effects (font (size 1 1) (thickness 0.15)))
+  )
+  (gr_text "Text in Dwgs.User" (at 149 68) (layer Dwgs.User)
+    (effects (font (size 1 1) (thickness 0.15)))
+  )
+  (gr_line (start 187.96 69.85) (end 142.24 69.85) (layer Edge.Cuts) (width 0.12))
+  (gr_line (start 187.96 91.44) (end 187.96 69.85) (layer Edge.Cuts) (width 0.12))
+  (gr_line (start 142.24 91.44) (end 187.96 91.44) (layer Edge.Cuts) (width 0.12))
+  (gr_line (start 142.24 69.85) (end 142.24 91.44) (layer Edge.Cuts) (width 0.12))
+
+  (segment (start 160 73) (end 180 73) (width 0.25) (layer GND.Cu) (net 0))
+  (segment (start 180 73) (end 180 88) (width 0.25) (layer GND.Cu) (net 0))
+  (segment (start 180 88) (end 160 88) (width 0.25) (layer Signal1.Cu) (net 0))
+  (segment (start 160 88) (end 160 73) (width 0.25) (layer Signal1.Cu) (net 0))
+  (segment (start 161 87) (end 179 87) (width 0.25) (layer Signal2.Cu) (net 0))
+  (segment (start 179 87) (end 179 74) (width 0.25) (layer Signal2.Cu) (net 0))
+  (segment (start 161 74) (end 179 74) (width 0.25) (layer Power.Cu) (net 0))
+  (segment (start 161 74) (end 161 87) (width 0.25) (layer Power.Cu) (net 0))
+  (segment (start 167.155 83.37) (end 165.1 81.315) (width 0.25) (layer F.Cu) (net 1))
+  (segment (start 167.155 83.82) (end 167.155 83.37) (width 0.25) (layer F.Cu) (net 1))
+  (segment (start 165.1 81.315) (end 164.775001 80.990001) (width 0.25) (layer F.Cu) (net 1))
+  (segment (start 164.775001 80.990001) (end 157.769999 80.990001) (width 0.25) (layer F.Cu) (net 1))
+  (segment (start 156.75 82.01) (end 154.94 82.01) (width 0.25) (layer F.Cu) (net 1))
+  (segment (start 157.769999 80.990001) (end 156.75 82.01) (width 0.25) (layer F.Cu) (net 1))
+  (segment (start 164.765 80.01) (end 164.775001 80.020001) (width 0.25) (layer F.Cu) (net 2))
+  (segment (start 154.94 80.01) (end 164.765 80.01) (width 0.25) (layer F.Cu) (net 2))
+  (segment (start 165.260001 79.535001) (end 170.18 79.535001) (width 0.25) (layer F.Cu) (net 2))
+  (segment (start 164.775001 80.020001) (end 165.260001 79.535001) (width 0.25) (layer F.Cu) (net 2))
+  (segment (start 170.18 81.765) (end 168.125 83.82) (width 0.25) (layer F.Cu) (net 3))
+  (segment (start 170.18 80.505001) (end 170.18 81.765) (width 0.25) (layer F.Cu) (net 3))
+
+)
diff --git a/tests/test_plot/test_simple_2layer.py b/tests/test_plot/test_gerber.py
similarity index 66%
rename from tests/test_plot/test_simple_2layer.py
rename to tests/test_plot/test_gerber.py
index f1c88f61..36debf09 100644
--- a/tests/test_plot/test_simple_2layer.py
+++ b/tests/test_plot/test_gerber.py
@@ -1,6 +1,7 @@
 """
-Tests of simple 2-layer PCBs.
-We generate the gerbers.
+Tests of Gerber format.
+- Simple 2 layers
+- Inner layer
 
 For debug information use:
 pytest-3 --log-cli-level debug
@@ -19,7 +20,7 @@ from utils import context
 GERBER_DIR = 'gerberdir'
 
 
-def test_2layer():
+def test_gerber_2layer():
     prj = 'simple_2layer'
     ctx = context.TestContext('Simple_2_layer', prj, prj, GERBER_DIR)
     ctx.run()
@@ -37,3 +38,14 @@ def test_2layer():
     ctx.expect_gerber_flash_at(f_cu, 5, (140, -100))
 
     ctx.clean_up()
+
+
+def test_gerber_inner():
+    prj = 'good-project'
+    ctx = context.TestContext('Gerber_Inner', prj, 'gerber_inner', GERBER_DIR)
+    ctx.run()
+
+    ctx.expect_out_file(ctx.get_gerber_filename('GND_Cu'))
+    ctx.expect_out_file(ctx.get_gerber_filename('Signal1'))
+    ctx.expect_out_file(ctx.get_gerber_job_filename())
+    ctx.clean_up()
diff --git a/tests/test_plot/test_yaml_errors.py b/tests/test_plot/test_yaml_errors.py
index f5ab17e9..16d680bd 100644
--- a/tests/test_plot/test_yaml_errors.py
+++ b/tests/test_plot/test_yaml_errors.py
@@ -1,7 +1,9 @@
 """
 Tests various errors in the config file
 
+- Wrong kiplot
 - No kiplot.version
+- Typo in kiplot.version
 - Wrong kiplot.version
 - Missing drill map type
 - Wrong drill map type
@@ -11,10 +13,29 @@ Tests various errors in the config file
   - Incorrect name
   - Inner.1, but no inner layers
   - Inner_1 (malformed)
+  - Not a list
+  - Unknown attribute
+  - No layer attribute
 - No output:
   - name
   - type
   - layers
+- Output:
+  - with unknown attribute
+  - Not a list
+- Filters:
+  - Not a list
+  - Empty number
+  - No number
+  - Empty regex
+  - No regex
+  - No filter
+- Pre-flight:
+  - Not a list
+  - Unknown entry
+  - Wrong type for entry (run_drc)
+- YAML syntax
+- Unknown section
 
 For debug information use:
 pytest-3 --log-cli-level debug
@@ -31,6 +52,9 @@ sys.path.insert(0, os.path.dirname(prev_dir))
 from kiplot.misc import (EXIT_BAD_CONFIG, PLOT_ERROR)
 
 
+PRJ = 'fail-project'
+
+
 def test_no_version():
     ctx = context.TestContext('ErrorNoVersion', '3Rs', 'error_no_version', None)
     ctx.run(EXIT_BAD_CONFIG)
@@ -45,6 +69,20 @@ def test_wrong_version():
     ctx.clean_up()
 
 
+def test_wrong_version_2():
+    ctx = context.TestContext('ErrorWrongVersion2', '3Rs', 'error_wrong_version_2', None)
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err('Incorrect .?kiplot.? section')
+    ctx.clean_up()
+
+
+def test_wrong_version_3():
+    ctx = context.TestContext('ErrorWrongVersion3', '3Rs', 'error_wrong_version_3', None)
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err('YAML config needs .?kiplot.version.?')
+    ctx.clean_up()
+
+
 def test_drill_map_no_type():
     ctx = context.TestContext('ErrorDrillMapNoType', '3Rs', 'error_drill_map_no_type', None)
     ctx.run(EXIT_BAD_CONFIG)
@@ -80,6 +118,27 @@ def test_wrong_layer_3():
     ctx.clean_up()
 
 
+def test_wrong_layer_4():
+    ctx = context.TestContext('ErrorWrongLayer4', '3Rs', 'error_wrong_layer_4', None)
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err(".?layers.? must be a list")
+    ctx.clean_up()
+
+
+def test_wrong_layer_5():
+    ctx = context.TestContext('ErrorWrongLayer5', '3Rs', 'error_wrong_layer_5', None)
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("Unknown .?bogus.? attribute ")
+    ctx.clean_up()
+
+
+def test_wrong_layer_6():
+    ctx = context.TestContext('ErrorWrongLayer6', '3Rs', 'error_wrong_layer_6', None)
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("Missing .?layer.? attribute")
+    ctx.clean_up()
+
+
 def test_no_name():
     ctx = context.TestContext('ErrorNoName', '3Rs', 'error_no_name', None)
     ctx.run(EXIT_BAD_CONFIG)
@@ -94,6 +153,13 @@ def test_no_type():
     ctx.clean_up()
 
 
+def test_out_unknown_attr():
+    ctx = context.TestContext('ErrorUnkOutAttr', '3Rs', 'error_unk_attr', None)
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("Unknown key .?types.?")
+    ctx.clean_up()
+
+
 # Now is valid
 # def test_no_options():
 #     ctx = context.TestContext('ErrorNoOptions', '3Rs', 'error_no_options', None)
@@ -121,3 +187,87 @@ def test_error_step_min_distance():
     ctx.run(EXIT_BAD_CONFIG)
     assert ctx.search_err("`min_distance` must be a number")
     ctx.clean_up()
+
+
+def test_filter_not_list():
+    ctx = context.TestContext('FilterNotList', PRJ, 'error_filter_not_list', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err(".?filters.? must be a list ")
+    ctx.clean_up()
+
+
+def test_filter_no_number():
+    ctx = context.TestContext('FilterNoNumber', PRJ, 'error_filter_no_number', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("empty .?number.? in .?filter.?")
+    ctx.clean_up()
+
+
+def test_filter_no_number_2():
+    ctx = context.TestContext('FilterNoNumber2', PRJ, 'error_filter_no_number_2', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("missing .?number.? for .?filter.?")
+    ctx.clean_up()
+
+
+def test_filter_no_regex():
+    ctx = context.TestContext('FilterNoRegex', PRJ, 'error_filter_no_regex', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("empty .?regex.? in .?filter.?")
+    ctx.clean_up()
+
+
+def test_filter_no_regex_2():
+    ctx = context.TestContext('FilterNoRegex2', PRJ, 'error_filter_no_regex_2', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("missing .?regex.? for .?filter.?")
+    ctx.clean_up()
+
+
+def test_filter_wrong_entry():
+    ctx = context.TestContext('FilterWrongEntry', PRJ, 'error_filter_wrong_entry', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err(".?filters.? section of .?preflight.? must contain .?filter.?(.*)Pad 2 of C4")
+    ctx.clean_up()
+
+
+def test_error_pre_list():
+    ctx = context.TestContext('ErrorPreList', PRJ, 'error_pre_list', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("Incorrect .?preflight.? section")
+    ctx.clean_up()
+
+
+def test_error_pre_unk():
+    ctx = context.TestContext('ErrorPreUnk', PRJ, 'error_pre_unk', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("Unknown preflight: .?run_drcs.?")
+    ctx.clean_up()
+
+
+def test_error_wrong_type_1():
+    ctx = context.TestContext('ErrorWrongType1', PRJ, 'error_pre_wrong_type_1', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("In preflight 'run_drc': must be boolean")
+    ctx.clean_up()
+
+
+def test_error_yaml():
+    ctx = context.TestContext('ErrorYAML', PRJ, 'error_yaml', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("Error loading YAML")
+    ctx.clean_up()
+
+
+def test_out_not_list():
+    ctx = context.TestContext('OutNotList', PRJ, 'error_out_not_list', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err(".?outputs.? must be a list")
+    ctx.clean_up()
+
+
+def test_unk_section():
+    ctx = context.TestContext('UnkSection', PRJ, 'error_unk_section', '')
+    ctx.run(EXIT_BAD_CONFIG)
+    assert ctx.search_err("Unknown section .?bogus.? in config")
+    ctx.clean_up()
diff --git a/tests/yaml_samples/error_filter_no_number.kiplot.yaml b/tests/yaml_samples/error_filter_no_number.kiplot.yaml
new file mode 100644
index 00000000..feb6be17
--- /dev/null
+++ b/tests/yaml_samples/error_filter_no_number.kiplot.yaml
@@ -0,0 +1,15 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  run_drc: true
+  filters:
+    - filter: 'Ignore C3 pad 2 too close to anything'
+      number:
+      regex:  'Pad 2 of C3'
+    - filter: 'Ignore unconnected pad 2 of C4'
+      number: 2
+      regex:  'Pad 2 of C4'
+
+
diff --git a/tests/yaml_samples/error_filter_no_number_2.kiplot.yaml b/tests/yaml_samples/error_filter_no_number_2.kiplot.yaml
new file mode 100644
index 00000000..49a69375
--- /dev/null
+++ b/tests/yaml_samples/error_filter_no_number_2.kiplot.yaml
@@ -0,0 +1,14 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  run_drc: true
+  filters:
+    - filter: 'Ignore C3 pad 2 too close to anything'
+      regex:  'Pad 2 of C3'
+    - filter: 'Ignore unconnected pad 2 of C4'
+      number: 2
+      regex:  'Pad 2 of C4'
+
+
diff --git a/tests/yaml_samples/error_filter_no_regex.kiplot.yaml b/tests/yaml_samples/error_filter_no_regex.kiplot.yaml
new file mode 100644
index 00000000..0a2fc0cb
--- /dev/null
+++ b/tests/yaml_samples/error_filter_no_regex.kiplot.yaml
@@ -0,0 +1,15 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  run_drc: true
+  filters:
+    - filter: 'Ignore C3 pad 2 too close to anything'
+      number: 2
+      regex:
+    - filter: 'Ignore unconnected pad 2 of C4'
+      number: 2
+      regex:  'Pad 2 of C4'
+
+
diff --git a/tests/yaml_samples/error_filter_no_regex_2.kiplot.yaml b/tests/yaml_samples/error_filter_no_regex_2.kiplot.yaml
new file mode 100644
index 00000000..f72b4c1c
--- /dev/null
+++ b/tests/yaml_samples/error_filter_no_regex_2.kiplot.yaml
@@ -0,0 +1,14 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  run_drc: true
+  filters:
+    - filter: 'Ignore C3 pad 2 too close to anything'
+      number: 2
+    - filter: 'Ignore unconnected pad 2 of C4'
+      number: 2
+      regex:  'Pad 2 of C4'
+
+
diff --git a/tests/yaml_samples/error_filter_not_list.kiplot.yaml b/tests/yaml_samples/error_filter_not_list.kiplot.yaml
new file mode 100644
index 00000000..f09bab22
--- /dev/null
+++ b/tests/yaml_samples/error_filter_not_list.kiplot.yaml
@@ -0,0 +1,15 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  run_drc: true
+  filters:
+      filter: 'Ignore C3 pad 2 too close to anything'
+      number: 4
+      regex:  'Pad 2 of C3'
+      filter: 'Ignore unconnected pad 2 of C4'
+      number: 2
+      regex:  'Pad 2 of C4'
+
+
diff --git a/tests/yaml_samples/error_filter_wrong_entry.kiplot.yaml b/tests/yaml_samples/error_filter_wrong_entry.kiplot.yaml
new file mode 100644
index 00000000..8f807059
--- /dev/null
+++ b/tests/yaml_samples/error_filter_wrong_entry.kiplot.yaml
@@ -0,0 +1,15 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  run_drc: true
+  filters:
+    - number: 4
+      filter: 'Ignore C3 pad 2 too close to anything'
+      regex:  'Pad 2 of C3'
+    - regex:  'Pad 2 of C4'
+      number: 2
+
+
+
diff --git a/tests/yaml_samples/error_out_not_list.kiplot.yaml b/tests/yaml_samples/error_out_not_list.kiplot.yaml
new file mode 100644
index 00000000..d1f17f67
--- /dev/null
+++ b/tests/yaml_samples/error_out_not_list.kiplot.yaml
@@ -0,0 +1,13 @@
+kiplot:
+  version: 1
+
+outputs:
+    name: PDF
+    comment: "PDF files"
+    type: pdf
+    dir: PDF
+    layers:
+      - layer: F.Cu
+        suffix: F_Cu
+      - layer: F.Bogus
+        suffix: B_Silks
diff --git a/tests/yaml_samples/error_pre_list.kiplot.yaml b/tests/yaml_samples/error_pre_list.kiplot.yaml
new file mode 100644
index 00000000..1512f010
--- /dev/null
+++ b/tests/yaml_samples/error_pre_list.kiplot.yaml
@@ -0,0 +1,9 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  - update_xml: true
+  - run_drc: false
+
+
diff --git a/tests/yaml_samples/error_pre_unk.kiplot.yaml b/tests/yaml_samples/error_pre_unk.kiplot.yaml
new file mode 100644
index 00000000..0f2a9bad
--- /dev/null
+++ b/tests/yaml_samples/error_pre_unk.kiplot.yaml
@@ -0,0 +1,9 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  update_xml: true
+  run_drcs: false
+
+
diff --git a/tests/yaml_samples/error_pre_wrong_type_1.kiplot.yaml b/tests/yaml_samples/error_pre_wrong_type_1.kiplot.yaml
new file mode 100644
index 00000000..6ede7b24
--- /dev/null
+++ b/tests/yaml_samples/error_pre_wrong_type_1.kiplot.yaml
@@ -0,0 +1,9 @@
+# Example KiPlot config file
+kiplot:
+  version: 1
+
+preflight:
+  update_xml: true
+  run_drc: 1
+
+
diff --git a/tests/yaml_samples/error_unk_attr.kiplot.yaml b/tests/yaml_samples/error_unk_attr.kiplot.yaml
new file mode 100644
index 00000000..d0749b82
--- /dev/null
+++ b/tests/yaml_samples/error_unk_attr.kiplot.yaml
@@ -0,0 +1,29 @@
+kiplot:
+  version: 1
+
+outputs:
+  - name: PDF
+    comment: "PDF files"
+    types: 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
+    layers:
+      - layer: F.Cu
+        suffix: F_Cu
+      - layer: F.Bogus
+        suffix: B_Silks
diff --git a/tests/yaml_samples/error_unk_section.kiplot.yaml b/tests/yaml_samples/error_unk_section.kiplot.yaml
new file mode 100644
index 00000000..ae591a23
--- /dev/null
+++ b/tests/yaml_samples/error_unk_section.kiplot.yaml
@@ -0,0 +1,27 @@
+# Drills and Gerber drills
+kiplot:
+  version: 1
+
+bogus:
+
+  - name: excellon_drill
+    comment: "Excellon drill files"
+    type: excellon
+    dir: Drill
+    options:
+      metric_units: true
+      pth_and_npth_single_file: false
+      use_aux_axis_as_origin: false
+      minimal_header: false
+      mirror_y_axis: false
+      report:
+        filename: 'report.rpt'
+      map:
+
+  - name: gerber_drills
+    comment: "Gerber drill files"
+    type: gerb_drill
+    dir: Drill
+    options:
+      use_aux_axis_as_origin: false
+
diff --git a/tests/yaml_samples/error_wrong_layer_4.kiplot.yaml b/tests/yaml_samples/error_wrong_layer_4.kiplot.yaml
new file mode 100644
index 00000000..6ad58d2f
--- /dev/null
+++ b/tests/yaml_samples/error_wrong_layer_4.kiplot.yaml
@@ -0,0 +1,29 @@
+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
+    layers:
+      layer: F.Cu
+      suffix: F_Cu
+      layer: Inner_1
+      suffix: B_Silks
diff --git a/tests/yaml_samples/error_wrong_layer_5.kiplot.yaml b/tests/yaml_samples/error_wrong_layer_5.kiplot.yaml
new file mode 100644
index 00000000..675abdae
--- /dev/null
+++ b/tests/yaml_samples/error_wrong_layer_5.kiplot.yaml
@@ -0,0 +1,30 @@
+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
+    layers:
+      - layer: F.Cu
+        description: 'Ok'
+      - layer: B.Cu
+        bogus: 'Wrong'
+
diff --git a/tests/yaml_samples/error_wrong_layer_6.kiplot.yaml b/tests/yaml_samples/error_wrong_layer_6.kiplot.yaml
new file mode 100644
index 00000000..c70113aa
--- /dev/null
+++ b/tests/yaml_samples/error_wrong_layer_6.kiplot.yaml
@@ -0,0 +1,31 @@
+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
+    layers:
+      - description: 'Not in order'
+        suffix: 'A_'
+        layer: F.Cu
+      - description: 'Where is my layer?'
+        suffix: 'A_'
+
diff --git a/tests/yaml_samples/error_wrong_version_2.kiplot.yaml b/tests/yaml_samples/error_wrong_version_2.kiplot.yaml
new file mode 100644
index 00000000..946ae124
--- /dev/null
+++ b/tests/yaml_samples/error_wrong_version_2.kiplot.yaml
@@ -0,0 +1,6 @@
+kiplot: 1
+
+preflight:
+  run_drc: true
+
+
diff --git a/tests/yaml_samples/error_wrong_version_3.kiplot.yaml b/tests/yaml_samples/error_wrong_version_3.kiplot.yaml
new file mode 100644
index 00000000..67db2b07
--- /dev/null
+++ b/tests/yaml_samples/error_wrong_version_3.kiplot.yaml
@@ -0,0 +1,7 @@
+kiplot:
+  versiona: 1
+
+preflight:
+  run_drc: true
+
+
diff --git a/tests/yaml_samples/error_yaml.kiplot.yaml b/tests/yaml_samples/error_yaml.kiplot.yaml
new file mode 100644
index 00000000..5256cdd6
--- /dev/null
+++ b/tests/yaml_samples/error_yaml.kiplot.yaml
@@ -0,0 +1,27 @@
+# Drills and Gerber drills
+kiplot:
+  version: 1
+
+outputs:
+
+  - name excellon_drill
+    comment: "Excellon drill files"
+    type: excellon
+    dir: Drill
+    options:
+      metric_units: true
+      pth_and_npth_single_file: false
+      use_aux_axis_as_origin: false
+      minimal_header: false
+      mirror_y_axis: false
+      report:
+        filename: 'report.rpt'
+      map:
+
+  - name: gerber_drills
+    comment: "Gerber drill files"
+    type: gerb_drill
+    dir: Drill
+    options:
+      use_aux_axis_as_origin: false
+
diff --git a/tests/yaml_samples/gerber_inner.kiplot.yaml b/tests/yaml_samples/gerber_inner.kiplot.yaml
new file mode 100644
index 00000000..00823b24
--- /dev/null
+++ b/tests/yaml_samples/gerber_inner.kiplot.yaml
@@ -0,0 +1,39 @@
+# Example KiPlot config file for a basic 2-layer board
+kiplot:
+  version: 1
+
+outputs:
+
+  - name: 'gerbers'
+    comment: "Gerbers for the Gerber god"
+    type: gerber
+    dir: gerberdir
+    options:
+      # generic layer 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
+
+      # gerber options
+      line_width: 0.15
+      subtract_mask_from_silk: true
+      use_protel_extensions: false
+      gerber_precision: 4.6
+      create_gerber_job_file: true
+      use_gerber_x2_attributes: true
+      use_gerber_net_attributes: false
+
+    layers:
+      - layer: GND.Cu
+        suffix: GND_Cu
+        description: 'Ground plane'
+      - layer: Inner.2
+        suffix: Signal1
+        description: 'Inner signals 1'
+