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unit_spec.rb
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unit_spec.rb
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require File.dirname(__FILE__) + '/../spec_helper'
describe Unit.base_units do
it {should be_a Array}
it {should have(14).elements}
%w{kilogram meter second ampere degK tempK mole candela each dollar steradian radian decibel byte}.each do |u|
it {should include(Unit(u))}
end
end
describe "Create some simple units" do
# zero string
describe Unit("0") do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should === 0}
its(:scalar) {should be_an Integer}
its(:units) {should be_empty}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should be_unitless}
it {should be_zero}
its(:base) {should == subject}
end
# non-zero string
describe Unit("1") do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should === 1}
its(:scalar) {should be_an Integer}
its(:units) {should be_empty}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should be_unitless}
it {should_not be_zero}
its(:base) {should == subject}
end
# numeric
describe Unit(1) do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should === 1}
its(:scalar) {should be_an Integer}
its(:units) {should be_empty}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should be_unitless}
it {should_not be_zero}
its(:base) {should == subject}
end
# rational
describe Unit(Rational(1,2)) do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should === Rational(1,2)}
its(:scalar) {should be_a Rational}
its(:units) {should be_empty}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should be_unitless}
it {should_not be_zero}
its(:base) {should == subject}
end
# float
describe Unit(0.5) do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should === 0.5}
its(:scalar) {should be_a Float}
its(:units) {should be_empty}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should be_unitless}
it {should_not be_zero}
its(:base) {should == subject}
end
# complex
describe Unit(Complex(1,1)) do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should === Complex(1,1)}
its(:scalar) {should be_a Complex}
its(:units) {should be_empty}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should be_unitless}
it {should_not be_zero}
its(:base) {should == subject}
end
# scalar and unit
describe Unit("1 mm") do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should == 1}
its(:scalar) {should be_an Integer}
its(:units) {should == "mm"}
its(:kind) {should == :length}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should == Unit("0.001 m")}
end
# with a zero power
describe Unit("1 m^0") do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should == 1}
its(:scalar) {should be_an Integer}
its(:units) {should == ""}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should be_unitless}
it {should_not be_zero}
its(:base) {should == Unit("1")}
end
# unit only
describe Unit("mm") do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should == 1}
its(:scalar) {should be_an Integer}
its(:units) {should == "mm"}
its(:kind) {should == :length}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should == Unit("0.001 m")}
end
# Compound unit
describe Unit("1 N*m") do
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should == 1}
its(:scalar) {should be_an Integer}
its(:units) {should == "N*m"}
its(:kind) {should == :energy}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should == Unit("1 kg*m^2/s^2")}
end
# scalar and unit with powers
describe Unit("10 m/s^2") do
it {should be_an_instance_of Unit}
its(:scalar) {should == 10}
its(:scalar) {should be_an Integer}
its(:units) {should == "m/s^2"}
its(:kind) {should == :acceleration}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should == Unit("10 m/s^2")}
end
# feet/in form
describe Unit("5ft 6in") do
it {should be_an_instance_of Unit}
its(:scalar) {should == 5.5}
its(:units) {should == "ft"}
its(:kind) {should == :length}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_within(Unit("0.01 m")).of Unit("1.6764 m")}
specify { subject.to_s(:ft).should == %{5'6"} }
end
# pound/ounces form
describe Unit("6lbs 5oz") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_within(0.001).of 6.312}
its(:units) {should == "lbs"}
its(:kind) {should == :mass}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_within(Unit("0.01 kg")).of Unit("2.8633 kg")}
specify { subject.to_s(:lbs).should == "6 lbs, 5 oz" }
end
# temperature
describe Unit("100 tempC") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_within(0.001).of 100}
its(:units) {should == "tempC"}
its(:kind) {should == :temperature}
it {should be_temperature}
it {should be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_within(Unit("0.01 degK")).of Unit("373.15 tempK")}
its(:temperature_scale) {should == "degC"}
end
# Time
describe Unit(Time.now) do
it {should be_an_instance_of Unit}
its(:scalar) {should be_a(Numeric)}
its(:units) {should == "s"}
its(:kind) {should == :time}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a(Numeric)}
its(:temperature_scale) {should be_nil}
end
# degrees
describe Unit("100 degC") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_within(0.001).of 100}
its(:units) {should == "degC"}
its(:kind) {should == :temperature}
it {should_not be_temperature}
it {should be_degree}
it {should_not be_base}
it {should_not be_unitless}
its(:base) {should be_within(Unit("0.01 degK")).of Unit("100 degK")}
end
# percent
describe Unit("75%") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Integer}
its(:units) {should == "%"}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a(Numeric)}
its(:temperature_scale) {should be_nil}
end
# angle
describe Unit("180 deg") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_a Numeric}
its(:units) {should == "deg"}
its(:kind) {should == :angle}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a(Numeric)}
its(:temperature_scale) {should be_nil}
end
# radians
describe Unit("1 radian") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_a Numeric}
its(:units) {should == "rad"}
its(:kind) {should == :angle}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
end
# counting
describe Unit("12 dozen") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Integer}
its(:units) {should == "doz"}
its(:kind) {should == :unitless}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
end
# rational scalar with unit
describe Unit("1/2 kg") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Rational}
its(:units) {should == "kg"}
its(:kind) {should == :mass}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
end
# rational scalar with compound unit
describe Unit("1/2 kg/m") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Rational}
its(:units) {should == "kg/m"}
its(:kind) {should be_nil}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
end
# time string
describe Unit("1:23:45") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Rational}
its(:units) {should == "h"}
its(:kind) {should == :time}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
end
# also '1 hours as minutes'
# '1 hour to minutes'
describe Unit.parse("1 hour in minutes") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Integer}
its(:units) {should == "min"}
its(:kind) {should == :time}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
end
# funky unit
describe Unit("1 attoparsec/microfortnight") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Integer}
its(:units) {should == "apc/ufortnight"}
its(:kind) {should == :speed}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
it { subject.convert_to("in/s").should be_within(Unit("0.0001 in/s")).of(Unit("1.0043269330917 in/s"))}
end
# Farads
describe Unit("1 F") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Integer}
its(:units) {should == "F"}
its(:kind) {should == :capacitance}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
end
describe Unit.new("1 m^2 s^-2") do
it {should be_an_instance_of Unit}
its(:scalar) {should be_an Integer}
its(:units) {should == "m^2/s^2"}
its(:kind) {should == :radiation}
it {should_not be_temperature}
it {should_not be_degree}
it {should be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should be_a Numeric}
its(:temperature_scale) {should be_nil}
end
end
describe "Unit handles attempts to create bad units" do
specify "no empty strings" do
expect {Unit("")}.to raise_error(ArgumentError,"No Unit Specified")
end
specify "no blank strings" do
expect {Unit(" ")}.to raise_error(ArgumentError,"No Unit Specified")
end
specify "no strings with tabs" do
expect {Unit("\t")}.to raise_error(ArgumentError,"No Unit Specified")
end
specify "no strings with newlines" do
expect {Unit("\n")}.to raise_error(ArgumentError,"No Unit Specified")
end
specify "no strings that don't specify a valid unit" do
expect {Unit("random string")}.to raise_error(ArgumentError,"'random string' Unit not recognized")
end
specify "no unhandled classes" do
expect {Unit(STDIN)}.to raise_error(ArgumentError,"Invalid Unit Format")
end
specify "no undefined units" do
expect {Unit("1 mFoo")}.to raise_error(ArgumentError,"'1 mFoo' Unit not recognized")
end
specify "no units with powers greater than 19" do
expect {Unit("1 m^20")}.to raise_error(ArgumentError, "Power out of range (-20 < net power of a unit < 20)")
end
specify "no units with powers less than 19" do
expect {Unit("1 m^-20")}.to raise_error(ArgumentError, "Power out of range (-20 < net power of a unit < 20)")
end
specify "no temperatures less than absolute zero" do
expect {Unit("-100 tempK")}.to raise_error(ArgumentError,"Temperatures must not be less than absolute zero")
expect {Unit("-100 tempR")}.to raise_error(ArgumentError,"Temperatures must not be less than absolute zero")
expect {Unit("-500/9 tempR")}.to raise_error(ArgumentError,"Temperatures must not be less than absolute zero")
end
end
describe Unit do
it "is a subclass of Numeric" do
described_class.should < Numeric
end
it "is Comparable" do
described_class.should < Comparable
end
describe "#defined?" do
it "should return true when asked about a defined unit" do
Unit.defined?("meter").should be_true
end
it "should return false when asked about a unit that is not defined" do
Unit.defined?("doohickey").should be_false
end
end
describe '#to_yaml' do
subject { Unit('1 mm') }
its(:to_yaml) {should =~ /--- !ruby\/object:Unit/ }
end
describe "#definition" do
context "The requested unit is defined" do
before(:each) do
@definition = Unit.definition('mph')
end
it "should return a Unit::Definition" do
@definition.should be_instance_of(Unit::Definition)
end
specify { @definition.name.should == "<mph>"}
specify { @definition.aliases.should == %w{mph}}
specify { @definition.numerator.should == ['<meter>'] }
specify { @definition.denominator.should == ['<second>'] }
specify { @definition.kind.should == :speed }
specify { @definition.scalar.should === 0.44704}
end
context "The requested unit is not defined" do
it "should return nil" do
Unit.definition("doohickey").should be_nil
end
end
end
describe "#define" do
describe "a new unit" do
before(:each) do
@jiffy = Unit.define("jiffy") do |jiffy|
jiffy.scalar = (1/100)
jiffy.aliases = %w{jif}
jiffy.numerator = ["<second>"]
jiffy.kind = :time
end
end
after(:each) do
Unit.undefine!('jiffy')
end
describe "Unit('1e6 jiffy')" do
# do this because the unit is not defined at the time this file is parsed, so it fails
subject {Unit("1e6 jiffy")}
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should == 1e6}
its(:scalar) {should be_an Integer}
its(:units) {should == "jif"}
its(:kind) {should == :time}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
its(:base) {should == Unit("10000 s")}
end
it "should register the new unit" do
Unit.defined?('jiffy').should be_true
end
end
describe "an existing unit again" do
before(:each) do
@cups = Unit.definition('cup')
@original_display_name = @cups.display_name
@cups.display_name = "cupz"
Unit.define(@cups)
end
after(:each) do
Unit.redefine!("cup") do |cup|
cup.display_name = @original_display_name
end
end
describe "Unit('1 cup')" do
# do this because the unit is going to be redefined
subject {Unit("1 cup")}
it {should be_a Numeric}
it {should be_an_instance_of Unit}
its(:scalar) {should == 1}
its(:scalar) {should be_an Integer}
its(:units) {should == "cupz"}
its(:kind) {should == :volume}
it {should_not be_temperature}
it {should_not be_degree}
it {should_not be_base}
it {should_not be_unitless}
it {should_not be_zero}
end
end
end
describe '#redefine!' do
before(:each) do
@jiffy = Unit.define("jiffy") do |jiffy|
jiffy.scalar = (1/100)
jiffy.aliases = %w{jif}
jiffy.numerator = ["<second>"]
jiffy.kind = :time
end
Unit.redefine!('jiffy') do |jiffy|
jiffy.scalar = (1/1000)
end
end
after(:each) do
Unit.undefine!("jiffy")
end
specify { Unit('1 jiffy').to_base.scalar.should == (1/1000) }
end
describe '#undefine!' do
before(:each) do
@jiffy = Unit.define("jiffy") do |jiffy|
jiffy.scalar = (1/100)
jiffy.aliases = %w{jif}
jiffy.numerator = ["<second>"]
jiffy.kind = :time
end
Unit.undefine!("jiffy")
end
specify "the unit should be undefined" do
Unit.defined?('jiffy').should be_false
end
specify "attempting to use an undefined unit fails" do
expect { Unit("1 jiffy") }.to raise_exception(ArgumentError)
end
it "should return true when undefining an unknown unit" do
Unit.defined?("unknown").should be_false
Unit.undefine!("unknown").should be_true
end
end
describe '#clone' do
subject { Unit('1 mm') }
its(:clone) {should === subject}
end
end
describe "Unit Comparisons" do
context "Unit should detect if two units are 'compatible' (i.e., can be converted into each other)" do
specify { Unit("1 ft").should =~ Unit('1 m')}
specify { Unit("1 ft").should =~ "m"}
specify { Unit("1 ft").should be_compatible_with Unit('1 m')}
specify { Unit("1 ft").should be_compatible_with "m"}
specify { Unit("1 m").should be_compatible_with Unit('1 kg*m/kg')}
specify { Unit("1 ft").should_not =~ Unit('1 kg')}
specify { Unit("1 ft").should_not be_compatible_with Unit('1 kg')}
specify { Unit("1 ft").should_not be_compatible_with nil}
end
context "Equality" do
context "with uncoercable objects" do
specify { Unit("1 mm").should_not == nil }
end
context "units of same kind" do
specify { Unit("1000 m").should == Unit('1 km')}
specify { Unit("100 m").should_not == Unit('1 km')}
specify { Unit("1 m").should == Unit('100 cm')}
end
context "units of incompatible types" do
specify { Unit("1 m").should_not == Unit("1 kg")}
end
context "units with a zero scalar are equal" do
specify {Unit("0 m").should == Unit("0 s")}
specify {Unit("0 m").should == Unit("0 kg")}
context "except for temperature units" do
specify {Unit("0 tempK").should == Unit("0 m")}
specify {Unit("0 tempR").should == Unit("0 m")}
specify {Unit("0 tempC").should_not == Unit("0 m")}
specify {Unit("0 tempF").should_not == Unit("0 m")}
end
end
end
context "Equivalence" do
context "units and scalars are the exactly the same" do
specify { Unit("1 m").should === Unit("1 m")}
specify { Unit("1 m").should be_same Unit("1 m")}
specify { Unit("1 m").should be_same_as Unit("1 m")}
end
context "units are compatible but not identical" do
specify { Unit("1000 m").should_not === Unit("1 km")}
specify { Unit("1000 m").should_not be_same Unit("1 km")}
specify { Unit("1000 m").should_not be_same_as Unit("1 km")}
end
context "units are not compatible" do
specify { Unit("1000 m").should_not === Unit("1 hour")}
specify { Unit("1000 m").should_not be_same Unit("1 hour")}
specify { Unit("1000 m").should_not be_same_as Unit("1 hour")}
end
context "scalars are different" do
specify { Unit("1 m").should_not === Unit("2 m")}
specify { Unit("1 m").should_not be_same Unit("2 m")}
specify { Unit("1 m").should_not be_same_as Unit("2 m")}
end
specify { Unit("1 m").should_not === nil}
end
context "Comparisons" do
context "compatible units can be compared" do
specify { Unit("1 m").should < Unit("2 m")}
specify { Unit("2 m").should > Unit("1 m")}
specify { Unit("1 m").should < Unit("1 mi")}
specify { Unit("2 m").should > Unit("1 ft")}
specify { Unit("70 tempF").should > Unit("10 degC")}
specify { Unit("1 m").should > 0 }
specify { expect { Unit("1 m").should_not > nil}.to raise_error(ArgumentError, /comparison of Unit with (nil failed|NilClass)/) }
end
context "incompatible units cannot be compared" do
specify { expect { Unit("1 m") < Unit("1 liter")}.to raise_error(ArgumentError,"Incompatible Units (m !~ l)")}
specify { expect { Unit("1 kg") > Unit("60 mph")}.to raise_error(ArgumentError,"Incompatible Units (kg !~ mph)")}
end
end
end
describe "Unit Conversions" do
context "between compatible units" do
specify { Unit("1 s").convert_to("ns").should == Unit("1e9 ns")}
specify { Unit("1 s").convert_to("ns").should == Unit("1e9 ns")}
specify { (Unit("1 s") >> "ns").should == Unit("1e9 ns")}
specify { Unit("1 m").convert_to(Unit("ft")).should be_within(Unit("0.001 ft")).of(Unit("3.28084 ft"))}
end
context "between incompatible units" do
specify { expect { Unit("1 s").convert_to("m")}.to raise_error(ArgumentError,"Incompatible Units")}
end
context "given bad input" do
specify { expect { Unit("1 m").convert_to("random string")}.to raise_error(ArgumentError,"'random string' Unit not recognized")}
specify { expect { Unit("1 m").convert_to(STDOUT)}.to raise_error(ArgumentError,"Unknown target units")}
end
context "between temperature scales" do
# note that 'temp' units are for temperature readings on a scale, while 'deg' units are used to represent
# differences between temperatures, offsets, or other differential temperatures.
specify { Unit("100 tempC").should be_within(Unit("0.001 degK")).of(Unit("373.15 tempK")) }
specify { Unit("0 tempC").should be_within(Unit("0.001 degK")).of(Unit("273.15 tempK")) }
specify { Unit("37 tempC").should be_within(Unit("0.01 degK")).of(Unit("310.15 tempK"))}
specify { Unit("-273.15 tempC").should == Unit("0 tempK") }
specify { Unit("212 tempF").should be_within(Unit("0.001 degK")).of(Unit("373.15 tempK")) }
specify { Unit("32 tempF").should be_within(Unit("0.001 degK")).of(Unit("273.15 tempK")) }
specify { Unit("98.6 tempF").should be_within(Unit("0.01 degK")).of(Unit("310.15 tempK"))}
specify { Unit("-459.67 tempF").should == Unit("0 tempK") }
specify { Unit("671.67 tempR").should be_within(Unit("0.001 degK")).of(Unit("373.15 tempK")) }
specify { Unit("491.67 tempR").should be_within(Unit("0.001 degK")).of(Unit("273.15 tempK")) }
specify { Unit("558.27 tempR").should be_within(Unit("0.01 degK")).of(Unit("310.15 tempK"))}
specify { Unit("0 tempR").should == Unit("0 tempK") }
specify { Unit("100 tempK").convert_to("tempC").should be_within(U"0.01 degC").of(Unit("-173.15 tempC"))}
specify { Unit("100 tempK").convert_to("tempF").should be_within(U"0.01 degF").of(Unit("-279.67 tempF"))}
specify { Unit("100 tempK").convert_to("tempR").should be_within(U"0.01 degR").of(Unit("180 tempR"))}
specify { Unit("1 degC").should == Unit("1 degK")}
specify { Unit("1 degF").should == Unit("1 degR")}
specify { Unit("1 degC").should == Unit("1.8 degR")}
specify { Unit("1 degF").should be_within(Unit("0.001 degK")).of(Unit("0.5555 degK"))}
end
context "reported bugs" do
specify { (Unit("189 Mtonne") * Unit("1189 g/tonne")).should == Unit("224721 tonne") }
specify { (Unit("189 Mtonne") * Unit("1189 g/tonne")).convert_to("tonne").should == Unit("224721 tonne") }
end
describe "Foot-inch conversions" do
[
["76 in", %Q{6'4"}],
["77 in", %Q{6'5"}],
["78 in", %Q{6'6"}],
["79 in", %Q{6'7"}],
["80 in", %Q{6'8"}],
["87 in", %Q{7'3"}],
["88 in", %Q{7'4"}],
["89 in", %Q{7'5"}]
].each do |inches, feet|
specify { Unit(inches).convert_to("ft").should == Unit(feet)}
specify { Unit(inches).to_s(:ft).should == feet}
end
end
describe "pound-ounce conversions" do
[
["76 oz", "4 lbs, 12 oz"],
["77 oz", "4 lbs, 13 oz"],
["78 oz", "4 lbs, 14 oz"],
["79 oz", "4 lbs, 15 oz"],
["80 oz", "5 lbs, 0 oz"],
["87 oz", "5 lbs, 7 oz"],
["88 oz", "5 lbs, 8 oz"],
["89 oz", "5 lbs, 9 oz"]
].each do |ounces, pounds|
specify { Unit(ounces).convert_to("lbs").should == Unit(pounds)}
specify { Unit(ounces).to_s(:lbs).should == pounds}
end
end
end
describe "Unit Math" do
context "operators:" do
context "addition (+)" do
context "between compatible units" do
specify { (Unit("0 m") + Unit("10 m")).should == Unit("10 m")}
specify { (Unit("5 kg") + Unit("10 kg")).should == Unit("15 kg")}
end
context "between a zero unit and another unit" do
specify { (Unit("0 kg") + Unit("10 m")).should == Unit("10 m")}
specify { (Unit("0 m") + Unit("10 kg")).should == Unit("10 kg")}
end
context "between incompatible units" do
specify { expect {Unit("10 kg") + Unit("10 m")}.to raise_error(ArgumentError)}
specify { expect {Unit("10 m") + Unit("10 kg")}.to raise_error(ArgumentError)}
specify { expect {Unit("10 m") + nil}.to raise_error(ArgumentError)}
end
context "a number from a unit" do
specify { expect { Unit("10 kg") + 1 }.to raise_error(ArgumentError)}
specify { expect { 10 + Unit("10 kg") }.to raise_error(ArgumentError)}
end
context "between a unit and coerceable types" do
specify { (Unit('10 kg') + %w{1 kg}).should == Unit('11 kg') }
specify { (Unit('10 kg') + "1 kg").should == Unit('11 kg') }
end
context "between two temperatures" do
specify { expect {(Unit("100 tempK") + Unit("100 tempK"))}.to raise_error(ArgumentError,"Cannot add two temperatures") }
end
context "between a temperature and a degree" do
specify { (Unit("100 tempK") + Unit("100 degK")).should == Unit("200 tempK") }
end
context "between a degree and a temperature" do
specify { (Unit("100 degK") + Unit("100 tempK")).should == Unit("200 tempK") }
end
end
context "subtracting (-)" do
context "compatible units" do
specify { (Unit("0 m") - Unit("10 m")).should == Unit("-10 m")}
specify { (Unit("5 kg") - Unit("10 kg")).should == Unit("-5 kg")}
end
context "a unit from a zero unit" do
specify { (Unit("0 kg") - Unit("10 m")).should == Unit("-10 m")}
specify { (Unit("0 m") - Unit("10 kg")).should == Unit("-10 kg")}
end
context "incompatible units" do
specify { expect {Unit("10 kg") - Unit("10 m")}.to raise_error(ArgumentError)}
specify { expect {Unit("10 m") - Unit("10 kg")}.to raise_error(ArgumentError)}
specify { expect {Unit("10 m") - nil}.to raise_error(ArgumentError)}
end
context "between a unit and coerceable types" do
specify { (Unit('10 kg') - %w{1 kg}).should == Unit('9 kg') }
specify { (Unit('10 kg') - "1 kg").should == Unit('9 kg') }
end
context "a number from a unit" do
specify { expect { Unit("10 kg") - 1 }.to raise_error(ArgumentError)}
specify { expect { 10 - Unit("10 kg") }.to raise_error(ArgumentError)}
end
context "between two temperatures" do
specify { (Unit("100 tempK") - Unit("100 tempK")).should == Unit("0 degK") }
end
context "between a temperature and a degree" do
specify { (Unit("100 tempK") - Unit("100 degK")).should == Unit("0 tempK") }
end
context "between a degree and a temperature" do
specify { expect {(Unit("100 degK") - Unit("100 tempK"))}.to raise_error(ArgumentError,"Cannot subtract a temperature from a differential degree unit")}
end
end
context "multiplying (*)" do
context "between compatible units" do
specify { (Unit("0 m") * Unit("10 m")).should == Unit("0 m^2")}
specify { (Unit("5 kg") * Unit("10 kg")).should == Unit("50 kg^2")}
end
context "between incompatible units" do
specify { (Unit("0 m") * Unit("10 kg")).should == Unit("0 kg*m")}
specify { (Unit("5 m") * Unit("10 kg")).should == Unit("50 kg*m")}
specify { expect {Unit("10 m") * nil}.to raise_error(ArgumentError)}
end
context "between a unit and coerceable types" do
specify { (Unit('10 kg') * %w{1 kg}).should == Unit('10 kg^2') }
specify { (Unit('10 kg') * "1 kg").should == Unit('10 kg^2') }
end
context "by a temperature" do
specify { expect { Unit("5 kg") * Unit("100 tempF")}.to raise_exception(ArgumentError) }
end
context "by a number" do
specify { (10 * Unit("5 kg")).should == Unit("50 kg")}
end
end
context "dividing (/)" do
context "compatible units" do
specify { (Unit("0 m") / Unit("10 m")).should == Unit(0)}
specify { (Unit("5 kg") / Unit("10 kg")).should == Rational(1,2)}
end
context "incompatible units" do
specify { (Unit("0 m") / Unit("10 kg")).should == Unit("0 m/kg")}
specify { (Unit("5 m") / Unit("10 kg")).should == Unit("1/2 m/kg")}
specify { expect {Unit("10 m") / nil}.to raise_error(ArgumentError)}
end
context "between a unit and coerceable types" do
specify { (Unit('10 kg^2') / %w{1 kg}).should == Unit('10 kg') }
specify { (Unit('10 kg^2') / "1 kg").should == Unit('10 kg') }
end
context "by a temperature" do
specify { expect { Unit("5 kg") / Unit("100 tempF")}.to raise_exception(ArgumentError) }
end
context "a number by a unit" do
specify { (10 / Unit("5 kg")).should == Unit("2 1/kg")}
end
context "a unit by a number" do
specify { (Unit("5 kg") / 2).should == Unit("2.5 kg")}
end
context "by zero" do
specify { expect { Unit("10 m") / 0}.to raise_error(ZeroDivisionError)}
specify { expect { Unit("10 m") / Unit("0 m")}.to raise_error(ZeroDivisionError)}
specify { expect { Unit("10 m") / Unit("0 kg")}.to raise_error(ZeroDivisionError)}
end
end
context "exponentiating (**)" do
specify "a temperature raises an execption" do
expect { Unit("100 tempK")**2 }.to raise_error(ArgumentError,"Cannot raise a temperature to a power")
end
context Unit("0 m") do
it { (subject**1).should == subject }
it { (subject**2).should == subject }
end
context Unit("1 m") do
it { (subject**0).should == 1 }
it { (subject**1).should == subject }
it { (subject**(-1)).should == 1/subject }
it { (subject**(2)).should == Unit("1 m^2")}
it { (subject**(-2)).should == Unit("1 1/m^2")}
specify { expect { subject**(1/2)}.to raise_error(ArgumentError, "Illegal root")}
# because 1 m^(1/2) doesn't make any sense
specify { expect { subject**(Complex(1,1))}.to raise_error(ArgumentError, "exponentiation of complex numbers is not yet supported.")}
specify { expect { subject**(Unit("1 m"))}.to raise_error(ArgumentError, "Invalid Exponent")}
end
context Unit("1 m^2") do
it { (subject**(Rational(1,2))).should == Unit("1 m")}
it { (subject**(0.5)).should == Unit("1 m")}
specify { expect { subject**(0.12345) }.to raise_error(ArgumentError,"Not a n-th root (1..9), use 1/n")}
specify { expect { subject**("abcdefg") }.to raise_error(ArgumentError,"Invalid Exponent")}
end