Test suite and BFs for Tektronix TDS5xx

Test suite with full coverage
- Tests for `get_hardcopy` routine is a bit creative, but couldn't
  find any manual entry for what is done there.

Bug fixes:
- Typos
- map(float, list_of_string) not allowed anymore, switched to directly
  transferring to `np.array` with specific `dtype`.
- `flush_input` in `read_waveform` replaced with reading one character.
  Manual states that newline character is present after binary block.
- Enums called with name instead of value -> fixed, now called properly
- `get_hardcopy` routine tried to unpack read data. However, the
  `read` routine already decodes it using "utf-8" as the default
  encoding already. Thus: need to encode again before using
  `struct.unpack` to unpack them.
- Class had `import time` and `from time import sleep` and used `sleep`
  and `time.sleep`. Used `import time`, which is useful to mock out
  sleep time.

instruments/tektronix/tektds5xx.py

@@ -39,7 +39,6 @@
 import operator
 import struct
 import time
-from time import sleep
 
 import numpy as np
 
@@ -70,7 +69,7 @@ def __init__(self, tek, idx):
     def read(self):
         """
         Gets the current measurement value of the channel, and returns a dict
-        of all relevent information
+        of all relevant information
 
         :rtype: `dict` of measurement parameters
         """
@@ -126,8 +125,7 @@ def read_waveform(self, bin_format=True):
                 self._parent.sendcmd('DAT:ENC ASCI')
                 raw = self._parent.query('CURVE?')
                 raw = raw.split(',')  # Break up comma delimited string
-                raw = map(float, raw)  # Convert each list element to int
-                raw = np.array(raw)  # Convert into numpy array
+                raw = np.array(raw, dtype=np.float)  # Convert into numpy array
             else:
                 # Set encoding to signed, big-endian
                 self._parent.sendcmd('DAT:ENC RIB')
@@ -137,7 +135,8 @@ def read_waveform(self, bin_format=True):
                 raw = self._parent.binblockread(data_width)
 
                 # pylint: disable=protected-access
-                self._parent._file.flush_input()  # Flush input buffer
+                # read line separation character
+                self._parent._file.read_raw(1)
 
             # Retrieve Y offset
             yoffs = self._parent.query('WFMP:{}:YOF?'.format(self.name))
@@ -244,7 +243,7 @@ def scale(self):
         """
         Gets/sets the scale setting for this channel.
 
-        :type: `TekTDS5xx.Impedance`
+        :type: `float`
         """
         return float(self._parent.query("CH{}:SCA?".format(self._idx)))
 
@@ -401,7 +400,7 @@ def sources(self):
         :rtype: `list`
         """
         active = []
-        channels = map(int, self.query('SEL?').split(';')[0:11])
+        channels = np.array(self.query('SEL?').split(';')[0:11], dtype=np.int)
         for idx in range(0, 4):
             if channels[idx]:
                 active.append(_TekTDS5xxChannel(self, idx))
@@ -432,7 +431,7 @@ def data_source(self):
     @data_source.setter
     def data_source(self, newval):
         if isinstance(newval, _TekTDS5xxDataSource):
-            newval = TekTDS5xx.Source[newval.name]
+            newval = TekTDS5xx.Source(newval.name)
         if not isinstance(newval, TekTDS5xx.Source):
             raise TypeError("Source setting must be a `TekTDS5xx.Source`"
                             " value, got {} instead.".format(type(newval)))
@@ -500,7 +499,7 @@ def trigger_coupling(self):
 
         :type: `TekTDS5xx.Coupling`
         """
-        return TekTDS5xx.Coupling[self.query("TRIG:MAI:EDGE:COUP?")]
+        return TekTDS5xx.Coupling(self.query("TRIG:MAI:EDGE:COUP?"))
 
     @trigger_coupling.setter
     def trigger_coupling(self, newval):
@@ -539,8 +538,9 @@ def trigger_source(self):
     @trigger_source.setter
     def trigger_source(self, newval):
         if not isinstance(newval, TekTDS5xx.Trigger):
-            raise TypeError("Trigger source setting must be a"
-                            "`TekTDS5xx.source` value, got {} instead.".format(type(newval)))
+            raise TypeError("Trigger source setting must be a "
+                            "`TekTDS5xx.Trigger` value, got {} "
+                            "instead.".format(type(newval)))
 
         self.sendcmd("TRIG:MAI:EDGE:SOU {}".format(newval.value))
 
@@ -557,7 +557,7 @@ def clock(self):
     @clock.setter
     def clock(self, newval):
         if not isinstance(newval, datetime):
-            raise ValueError("Expected datetime.datetime"
+            raise ValueError("Expected datetime.datetime "
                              "but got {} instead".format(type(newval)))
         self.sendcmd(newval.strftime('DATE "%Y-%m-%d";:TIME "%H:%M:%S"'))
 
@@ -573,7 +573,7 @@ def display_clock(self):
     @display_clock.setter
     def display_clock(self, newval):
         if not isinstance(newval, bool):
-            raise ValueError("Expected bool but got"
+            raise ValueError("Expected bool but got "
                              "{} instead".format(type(newval)))
         self.sendcmd('DISPLAY:CLOCK {}'.format(int(newval)))
 
@@ -585,13 +585,14 @@ def get_hardcopy(self):
         """
         self.sendcmd('HARDC:PORT GPI;HARDC:LAY PORT;:HARDC:FORM BMP')
         self.sendcmd('HARDC START')
-        sleep(1)
+        time.sleep(1)
         header = self.query("", size=54)
+        header = header.encode("utf-8")
         # Get BMP Length  in kilobytes from DIB header, because file header is
         # bad
         length = reduce(
             operator.mul, struct.unpack('<iihh', header[18:30])) / 8
         length = int(length) + 8  # Add 8 bytes for our monochrome colour table
-        data = header + self.query("", size=length)
+        data = header + self.query("", size=length).encode("utf-8")
         self._file.flush_input()  # Flush input buffer
         return data