spec/dydx_spec.rb in dydx-0.1.3 vs spec/dydx_spec.rb in dydx-0.1.4

@@ -3,37 +3,18 @@
 describe Dydx do
   it 'has a version number' do
     expect(Dydx::VERSION).not_to be nil
   end
 
-  context 'ex1' do
-    $a = (:x ^ :n)
-    let(:d1){ da/dx }
-    let(:d2){ d/dx($a) }
-    it{ expect(d1.to_s).to eq('( n * ( x ^ ( n - 1 ) ) )') }
-    it{ expect(d2.to_s).to eq('( n * ( x ^ ( n - 1 ) ) )') }
-  end
+  it 'demo' do
+    f(x, y) <= x + x * y + y
+    expect(f(x, y)).to eq(x * (1 + y) + y)
+    expect(f(a, 2)).to eq(3 * a + 2)
+    expect(f(1, a + b)).to eq(1 + 2 * ( a + b ))
+    expect(f(1, 2)).to eq(5)
+    expect(d/dx(f(x, y))).to eq(1 + y)
 
-  context 'ex2' do
-    $b = (:x ^ (:x * 2))
-    let(:d1){ db/dx }
-    let(:d2){ d/dx($b) }
-    it{ expect(d1.to_s).to eq('( ( 2 * x ) * ( x ^ ( ( 2 * x ) - 1 ) ) )') }
-    it{ expect(d2.to_s).to eq('( ( 2 * x ) * ( x ^ ( ( 2 * x ) - 1 ) ) )') }
-  end
-
-  context 'ex3' do
-    $c = (:t ^ 2) / 2
-    let(:d1){ dc/dt }
-    let(:d2){ d/dt($c) }
-    it{ expect(d1.to_s).to eq('t') }
-    it{ expect(d2.to_s).to eq('t') }
-  end
-
-  context 'ex4' do
-    $i = 2 * (e ^ (2 * :z))
-    let(:d1){ di/dz }
-    let(:d2){ d/dz($i) }
-    it{ expect(d1.to_s).to eq('( 4 * ( e ^ ( 2 * z ) ) )') }
-    it{ expect(d2.to_s).to eq('( 4 * ( e ^ ( 2 * z ) ) )') }
+    g(x) <= sin(x)
+    expect(d/dx(g(x))).to eq(cos(x))
+    expect(S(g(x), dx)[0, pi / 2]).to eq(1.0)
   end
 end