fix first issue #667 (not second one!) (#668)

Author: ebroecker

src/canmatrix/formats/arxml.py

@@ -77,7 +77,6 @@ def fill_caches(self, start_element=None, ar_path=""):
 
     def open(self, filename):
         self.tree = lxml.etree.parse(filename)
-
         self.root = self.tree.getroot()  # type: _Element
 
         self.ns = "{" + self.tree.xpath('namespace-uri(.)') + "}"  # type: str
@@ -1017,15 +1016,21 @@ def decode_compu_method(compu_method, ea, float_factory):
         # keyword definition. 06Jun16
         #####################################################################################################
 
-        if ll is not None and desc is not None and canmatrix.utils.decode_number(ul.text,
+        if len(desc) == 0:
+            vt = ea.get_sub_by_name(compu_scale, 'VT')
+            if vt is not None:
+                desc = vt.text
+
+        rational = ea.get_child(compu_scale, "COMPU-RATIONAL-COEFFS")
+
+        if rational is None and ll is not None and desc is not None and canmatrix.utils.decode_number(ul.text,
                                                                                  float_factory) == canmatrix.utils.decode_number(
             ll.text, float_factory):
             #####################################################################################################
             #####################################################################################################
             values[ll.text] = desc
 
         # scale_desc = ea.get_element_desc(compu_scale)
-        rational = ea.get_child(compu_scale, "COMPU-RATIONAL-COEFFS")
         if rational is not None:
             numerator_parent = ea.get_child(rational, "COMPU-NUMERATOR")
             numerator = ea.get_children(numerator_parent, "V")

src/canmatrix/tests/ARXMLCompuMethod1.arxml

@@ -0,0 +1,42 @@
+<?xml version='1.0' encoding='ASCII'?>
+<AUTOSAR xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://autosar.org/3.2.3" xsi:schemaLocation="http://autosar.org/3.2.3 AUTOSAR_323.xsd">
+<AR-PACKAGE>
+            <COMPU-METHOD>
+              <SHORT-NAME>New_Frame_NewPDU_NewSignal_Encoding</SHORT-NAME>
+              <CATEGORY>SCALE_LINEAR_AND_TEXTTABLE</CATEGORY>
+
+              <COMPU-INTERNAL-TO-PHYS>
+                <COMPU-SCALES>
+                  <COMPU-SCALE>
+                    <LOWER-LIMIT INTERVAL-TYPE="CLOSED">0</LOWER-LIMIT>
+                    <UPPER-LIMIT INTERVAL-TYPE="CLOSED">0</UPPER-LIMIT>
+                    <COMPU-CONST>
+                      <VT>no trailer detected</VT>
+                    </COMPU-CONST>
+                  </COMPU-SCALE>
+                  <COMPU-SCALE>
+                    <LOWER-LIMIT INTERVAL-TYPE="CLOSED">1</LOWER-LIMIT>
+                    <UPPER-LIMIT INTERVAL-TYPE="CLOSED">1</UPPER-LIMIT>
+                    <COMPU-CONST>
+                      <VT>trailer detected</VT>
+                    </COMPU-CONST>
+                  </COMPU-SCALE>
+                  <COMPU-SCALE>
+                    <SHORT-LABEL>TrailerPresence</SHORT-LABEL>
+                    <LOWER-LIMIT INTERVAL-TYPE="CLOSED">0</LOWER-LIMIT>
+                    <UPPER-LIMIT INTERVAL-TYPE="CLOSED">0</UPPER-LIMIT>
+                    <COMPU-RATIONAL-COEFFS>
+                      <COMPU-NUMERATOR>
+                        <V>17</V>
+                        <V>42</V>
+                      </COMPU-NUMERATOR>
+                      <COMPU-DENOMINATOR>
+                        <V>1</V>
+                      </COMPU-DENOMINATOR>
+                    </COMPU-RATIONAL-COEFFS>
+                  </COMPU-SCALE>
+                </COMPU-SCALES>
+              </COMPU-INTERNAL-TO-PHYS>
+            </COMPU-METHOD>
+</AR-PACKAGE>
+</AUTOSAR>

src/canmatrix/tests/test_arxml.py

@@ -27,14 +27,25 @@ def test_get_signals_from_container_i_pdu():
     assert matrix["New_CanCluster"].frames[0].pdus[0].signals[0].attributes["SysSignalName"] == 'PDU_Contained_1_Signal1_905db81da40081cb'
 
 
-
 def test_get_signals_from_secured_pdu():
     here = Path(__file__).parent
     matrix = canmatrix.formats.arxml.load(str(here / "ARXMLSecuredPDUTest.arxml"))
     assert matrix["CAN"].frames[0].signals[0].name == 'someTestSignal'
     assert matrix["CAN"].frames[0].signals[1].name == 'Signal'
 
+
 def test_min_max():
     here = Path(__file__).parent
     matrix = canmatrix.formats.arxml.load(str(here / "ARXML_min_max.arxml"))
-    assert matrix["New_CanCluster"].frames[0].signals[0].is_signed == False
+    assert matrix["New_CanCluster"].frames[0].signals[0].is_signed is False
+
+
+def test_decode_compu_method_1():
+    here = Path(__file__).parent
+    ea = canmatrix.formats.arxml.Earxml()
+    ea.open(str(here / "ARXMLCompuMethod1.arxml"))
+    compu_method = ea.find("COMPU-METHOD")
+    values, factor, offset, unit, const = canmatrix.formats.arxml.decode_compu_method(compu_method, ea, float)
+    assert values == {'0': 'no trailer detected', '1': 'trailer detected'}
+    assert factor == 42
+    assert offset == 17