# ex08PhillConrad.py    Define some functions involving pi, sin, cos etc.
# P. Conrad for CS5nm, UCSB, Fall 2008
# 10/14/2008


# @@@ Something is missing here.. something you need in order to use
#   math.pi and math.fabs (remove this comment after you put it in)


# First, we define functions that run our test cases
# Note that \ character at the end of a line means that the line continues
# on the next line


# check_expect checks whether a function produces the expected result
# consumes:
#     test: a string describing the test
#    check: the value we are testing (typically result of a function call)
#   expect: the value we are expecting (typically a literal value)
# produces:
#    nothing (there is no return value)
# side effect:
#    prints a message indicating whether the test passed or failed

def check_expect(test,check,expect):
    if (check == expect):
        print "Test " + test + " passed."
    else:
        print "Test " + test + " failed: expected " + str(expect)  + \
              " but I got " + str(check)


# check_expect_within_tolerance
#    checks whether a function produces the expected result
#    but allows some degree of inaccuracy (a "tolerance")
#    in cases where calculating the exact result may not be feasible
#    (e.g. quantities involving pi, square roots, etc.)
# consumes:
#        test: a string describing the test
#       check: the value we are testing (typically result of a function call)
#      expect: the value we are expecting (typically a literal value)
#  toleranace: the largest inaccuracy that is permitted
# produces:
#    nothing (there is no return value)
# side effect:
#    prints a message indicating whether the test passed or failed


def check_expect_within_tolerance(test,check,expect,tolerance):
    if (math.fabs(check-expect) <= tolerance):
        print "Test " + test + " passed (with tolerance " + \
              str(tolerance) + ")"
    else:
        print "Test " + test + " failed: expected " + str(expect)  + \
              " but I got " + str(check) + " (tolerance of  " + \
            str(tolerance) + " exceeded)"


# Next define a function for the perimeter of a rectangle
#  consumes: radius of the circle
#  produces: area of the circle

def areaOfCircle(radius):
        return math.pi * radius ** 2

# Next, here are some test cases for areaOfCircle.
# These test cases are likely to fail because we have not allowed
# for the fact that the estimate of pi used in the calculation is
# less accurate than the one that Python uses.

check_expect("areaOfCircle test 1", areaOfCircle(1), 3.14159)
check_expect("areaOfCircle test 2", areaOfCircle(2), 12.56636)

# Here, by contrast are some test cases for areaOfCircle that will pass:

check_expect_within_tolerance("areaOfCircle test 3",
                            areaOfCircle(1), 3.14159, 0.0001)
check_expect_within_tolerance("areaOfCircle test 4",
                              areaOfCircle(2), 12.56636, 0.0001)


# Next, there are two functions that you must finish.
# In each case, one test case has been written for you.
# Add at least two additional test cases.
# It is better to write the test cases BEFORE you write the functions.
# Use the internet to look up the correct formulas, and use a calculator
#  to compute the correct values.    Choose an appropriate tolerance

# degreesToRadians converts degrees to radians
#  consumes:  degrees, the number of degrees in some angle
#  produces:  radians, the number of radians in an equivalent angle
def degreesToRadians(degrees):
    return -1; # a stub  @@@ REPLACE THIS WITH THE CORRECT RESULT

check_expect_within_tolerance("degreesToRadians test 1",
                            degreesToRadians(180), 3.14159, 0.0001)
                            # 180 degrees is "pi" radians
                            
# @@@ ADD TWO MORE TEST CASES HERE, THEN REMOVE THIS COMMENT

# distanceTravelled figures out how far you travelled, given rate and time
#  consumes:
#    rate (the speed at which you are travelling, e.g. in mph)
#    time (the amount of time you have been travelling at that speed, e.g. in hours)
#  produces:
#    the distance travelled
# Note that the units must be consistent between the rate, time and distance,
# e.g. if you use hours, you must always use hours, if you use seconds, you must
# always use seconds, and if you use meters or miles, you must the same units
# throughout

def distanceTravelled(rate, time):
    return -1 # stub

                            

check_expect_within_tolerance("distanceTravelled test case 1",
                                distanceTravelled(50, 2), 100, 0.000001)

# @@@ ADD TWO MORE TEST CASES HERE, THEN REMOVE THIS COMMENT


# Finally, add a function here to compute gas mileage.
# Add a comment before the function that indicates what the function
#  does, and what it consumes and what it produces.
# What a function "consumes" is a description of all of its parameters
# What a function "produces" is a description of what it returns.

# @@@ ADD COMMENT ABOUT YOUR GAS MILEAGE FUNCTION HERE

# @@@ ADD FUNCTION DEFINITION FOR GAS MILEAGE FUNCTION HERE

# @@@ ADD TEST CASES FOR GAS MILEAGE FUNCTION HERE ( at least two)