diff --git a/spec/build_tests_spec.rb b/spec/build_tests_spec.rb
index a9fff81..c4b176a 100644
--- a/spec/build_tests_spec.rb
+++ b/spec/build_tests_spec.rb
@@ -82,7 +82,7 @@ describe Rscons do
     Rscons::Environment.new do |env|
       env.Program('simple', Dir['*.c'])
     end
-    expect(File.exists?('simple.o')).to be_true
+    expect(File.exists?('simple.o')).to be_truthy
     expect(`./simple`).to eq "This is a simple C program\n"
   end
 
@@ -114,7 +114,7 @@ describe Rscons do
     Rscons::Environment.new do |env|
       env.Program('header', Dir['*.c'])
     end
-    expect(File.exists?('header.o')).to be_true
+    expect(File.exists?('header.o')).to be_truthy
     expect(`./header`).to eq "The value is 2\n"
   end
 
@@ -183,8 +183,8 @@ describe Rscons do
       env.Program('build_dir', Dir['src/**/*.c'])
     end
     expect(`./build_dir`).to eq "Hello from two()\n"
-    expect(File.exists?('build_one/one.o')).to be_true
-    expect(File.exists?('build_two/two.o')).to be_true
+    expect(File.exists?('build_one/one.o')).to be_truthy
+    expect(File.exists?('build_two/two.o')).to be_truthy
   end
 
   it 'uses build directories before build root' do
@@ -234,14 +234,14 @@ describe Rscons do
       env.Program('build_dir', Dir['src/**/*.c'])
     end
     expect(`./build_dir`).to eq "Hello from two()\n"
-    expect(File.exists?('build_one/one.o')).to be_true
-    expect(File.exists?('build_two/two.o')).to be_true
+    expect(File.exists?('build_one/one.o')).to be_truthy
+    expect(File.exists?('build_two/two.o')).to be_truthy
     Rscons.clean
-    expect(File.exists?('build_one/one.o')).to be_false
-    expect(File.exists?('build_two/two.o')).to be_false
-    expect(File.exists?('build_one')).to be_false
-    expect(File.exists?('build_two')).to be_false
-    expect(File.exists?('src/one/one.c')).to be_true
+    expect(File.exists?('build_one/one.o')).to be_falsey
+    expect(File.exists?('build_two/two.o')).to be_falsey
+    expect(File.exists?('build_one')).to be_falsey
+    expect(File.exists?('build_two')).to be_falsey
+    expect(File.exists?('src/one/one.c')).to be_truthy
   end
 
   it 'does not clean created directories if other non-rscons-generated files reside there' do
@@ -252,15 +252,15 @@ describe Rscons do
       env.Program('build_dir', Dir['src/**/*.c'])
     end
     expect(`./build_dir`).to eq "Hello from two()\n"
-    expect(File.exists?('build_one/one.o')).to be_true
-    expect(File.exists?('build_two/two.o')).to be_true
+    expect(File.exists?('build_one/one.o')).to be_truthy
+    expect(File.exists?('build_two/two.o')).to be_truthy
     File.open('build_two/tmp', 'w') { |fh| fh.puts "dum" }
     Rscons.clean
-    expect(File.exists?('build_one/one.o')).to be_false
-    expect(File.exists?('build_two/two.o')).to be_false
-    expect(File.exists?('build_one')).to be_false
-    expect(File.exists?('build_two')).to be_true
-    expect(File.exists?('src/one/one.c')).to be_true
+    expect(File.exists?('build_one/one.o')).to be_falsey
+    expect(File.exists?('build_two/two.o')).to be_falsey
+    expect(File.exists?('build_one')).to be_falsey
+    expect(File.exists?('build_two')).to be_truthy
+    expect(File.exists?('src/one/one.c')).to be_truthy
   end
 
   it 'allows Ruby classes as custom builders to be used to construct files' do
@@ -283,7 +283,7 @@ EOF
     end
 
     expect(lines).to eq ["CC program.o", "LD program#{env["PROGSUFFIX"]}"]
-    expect(File.exists?('inc.h')).to be_true
+    expect(File.exists?('inc.h')).to be_truthy
     expect(`./program`).to eq "The value is 5678\n"
   end
 
@@ -310,8 +310,8 @@ EOF
     end
 
     expect(lines).to eq ["CHGen inc.c", "CC program.o", "CC inc.o", "LD program#{env["PROGSUFFIX"]}"]
-    expect(File.exists?("inc.c")).to be_true
-    expect(File.exists?("inc.h")).to be_true
+    expect(File.exists?("inc.c")).to be_truthy
+    expect(File.exists?("inc.h")).to be_truthy
     expect(`./program`).to eq "The value is 42\n"
 
     File.open("inc.c", "w") {|fh| fh.puts "int THE_VALUE = 33;"}
@@ -372,7 +372,7 @@ EOF
     Rscons::Environment.new do |env|
       env.Program('simple', Dir['*.cc'])
     end
-    expect(File.exists?('simple.o')).to be_true
+    expect(File.exists?('simple.o')).to be_truthy
     expect(`./simple`).to eq "This is a simple C++ program\n"
   end
 
@@ -387,7 +387,7 @@ EOF
       'gcc -c -o two.o -MMD -MF two.mf two.c',
       "gcc -o two_sources#{env["PROGSUFFIX"]} one.o two.o",
     ]
-    expect(File.exists?("two_sources#{env["PROGSUFFIX"]}")).to be_true
+    expect(File.exists?("two_sources#{env["PROGSUFFIX"]}")).to be_truthy
     expect(`./two_sources`).to eq "This is a C program with two sources.\n"
   end
 
@@ -404,7 +404,7 @@ EOF
       'gcc -c -o three.o -MMD -MF three.mf three.c',
       "gcc -o library#{env["PROGSUFFIX"]} lib.a three.o",
     ]
-    expect(File.exists?("library#{env["PROGSUFFIX"]}")).to be_true
+    expect(File.exists?("library#{env["PROGSUFFIX"]}")).to be_truthy
     expect(`ar t lib.a`).to eq "one.o\ntwo.o\n"
   end
 
@@ -423,7 +423,7 @@ EOF
       env.Program('build_hook.exe', Dir['src/**/*.c'])
     end
     expect(`./build_hook`).to eq "Hello from two()\n"
-    lines.should =~ [
+    expect(lines).to match_array [
       'gcc -c -o build_one/one.o -MMD -MF build_one/one.mf -Isrc/one/ -Isrc/two/ -O1 src/one/one.c',
       'gcc -c -o build_two/two.o -MMD -MF build_two/two.mf -Isrc/one/ -Isrc/two/ -O2 src/two/two.c',
       'gcc -o build_hook.exe build_one/one.o build_two/two.o',
@@ -439,7 +439,7 @@ EOF
       end
     end
     expect(lines).to eq ["CC simple.o", "LD simple.exe"]
-    expect(File.exists?('simple.o')).to be_true
+    expect(File.exists?('simple.o')).to be_truthy
     expect(`./simple.exe`).to eq "This is a simple C program\n"
     e2 = Rscons::Environment.new do |env|
       program = env.Program('simple.exe', Dir['*.c'])
@@ -480,8 +480,8 @@ EOF
       env.Object("simple.o", "simple.c")
       env.Disassemble("simple.txt", "simple.o")
     end
-    expect(File.exists?("simple.txt")).to be_true
-    File.read("simple.txt").should =~ /Disassembly of section .text:/
+    expect(File.exists?("simple.txt")).to be_truthy
+    expect(File.read("simple.txt")).to match /Disassembly of section .text:/
   end
 
   it "supports preprocessing C sources" do
@@ -490,7 +490,7 @@ EOF
       env.Preprocess("simplepp.c", "simple.c")
       env.Program("simple", "simplepp.c")
     end
-    File.read("simplepp.c").should =~ /# \d+ "simple.c"/
+    expect(File.read("simplepp.c")).to match /# \d+ "simple.c"/
     expect(`./simple`).to eq "This is a simple C program\n"
   end
 
@@ -500,7 +500,7 @@ EOF
       env.Preprocess("simplepp.cc", "simple.cc")
       env.Program("simple", "simplepp.cc")
     end
-    File.read("simplepp.cc").should =~ /# \d+ "simple.cc"/
+    expect(File.read("simplepp.cc")).to match /# \d+ "simple.cc"/
     expect(`./simple`).to eq "This is a simple C++ program\n"
   end
 
@@ -540,7 +540,7 @@ EOF
     end
 
     expect(lines).to eq ["CC program.o", "LD program#{env["PROGSUFFIX"]}"]
-    expect(File.exists?('inc.h')).to be_true
+    expect(File.exists?('inc.h')).to be_truthy
     expect(`./program`).to eq "The value is 678\n"
   end
 end
diff --git a/spec/rscons/builders/cfile_spec.rb b/spec/rscons/builders/cfile_spec.rb
index 5605ca4..93ac23a 100644
--- a/spec/rscons/builders/cfile_spec.rb
+++ b/spec/rscons/builders/cfile_spec.rb
@@ -5,18 +5,18 @@ module Rscons
       subject {CFile.new}
 
       it "invokes bison to create a .c file from a .y file" do
-        subject.should_receive(:standard_build).with("YACC parser.c", "parser.c", ["bison", "-d", "-o", "parser.c", "parser.y"], ["parser.y"], env, :cache)
+        expect(subject).to receive(:standard_build).with("YACC parser.c", "parser.c", ["bison", "-d", "-o", "parser.c", "parser.y"], ["parser.y"], env, :cache)
         subject.run("parser.c", ["parser.y"], :cache, env, {})
       end
 
       it "invokes a custom lexer to create a .cc file from a .ll file" do
         env["LEX"] = "custom_lex"
-        subject.should_receive(:standard_build).with("LEX lexer.cc", "lexer.cc", ["custom_lex", "-o", "lexer.cc", "parser.ll"], ["parser.ll"], env, :cache)
+        expect(subject).to receive(:standard_build).with("LEX lexer.cc", "lexer.cc", ["custom_lex", "-o", "lexer.cc", "parser.ll"], ["parser.ll"], env, :cache)
         subject.run("lexer.cc", ["parser.ll"], :cache, env, {})
       end
 
       it "supports overriding construction variables" do
-        subject.should_receive(:standard_build).with("LEX lexer.c", "lexer.c", ["hi", "parser.l"], ["parser.l"], env, :cache)
+        expect(subject).to receive(:standard_build).with("LEX lexer.c", "lexer.c", ["hi", "parser.l"], ["parser.l"], env, :cache)
         subject.run("lexer.c", ["parser.l"], :cache, env, "LEX_CMD" => ["hi", "${_SOURCES}"])
       end
 
diff --git a/spec/rscons/builders/disassemble_spec.rb b/spec/rscons/builders/disassemble_spec.rb
index de7c350..a4f759e 100644
--- a/spec/rscons/builders/disassemble_spec.rb
+++ b/spec/rscons/builders/disassemble_spec.rb
@@ -9,7 +9,7 @@ module Rscons
         cache.stub(:up_to_date?) { false }
         cache.stub(:mkdir_p) { }
         cache.stub(:register_build) { }
-        env.should_receive(:execute).with("Disassemble a_file.txt", ["my_disasm", "a_file.exe"], anything).and_return(true)
+        expect(env).to receive(:execute).with("Disassemble a_file.txt", ["my_disasm", "a_file.exe"], anything).and_return(true)
         subject.run("a_file.txt", ["a_file.exe"], cache, env, "DISASM_CMD" => ["my_disasm", "${_SOURCES}"])
       end
     end
diff --git a/spec/rscons/builders/library_spec.rb b/spec/rscons/builders/library_spec.rb
index 8fe4e35..c8d82f1 100644
--- a/spec/rscons/builders/library_spec.rb
+++ b/spec/rscons/builders/library_spec.rb
@@ -5,12 +5,12 @@ module Rscons
       subject {Library.new}
 
       it "supports overriding AR construction variable" do
-        subject.should_receive(:standard_build).with("AR prog.a", "prog.a", ["sp-ar", "rcs", "prog.a", "prog.o"], ["prog.o"], env, :cache)
+        expect(subject).to receive(:standard_build).with("AR prog.a", "prog.a", ["sp-ar", "rcs", "prog.a", "prog.o"], ["prog.o"], env, :cache)
         subject.run("prog.a", ["prog.o"], :cache, env, "AR" => "sp-ar")
       end
 
       it "supports overriding ARCMD construction variable" do
-        subject.should_receive(:standard_build).with("AR prog.a", "prog.a", ["special", "AR!", "prog.o"], ["prog.o"], env, :cache)
+        expect(subject).to receive(:standard_build).with("AR prog.a", "prog.a", ["special", "AR!", "prog.o"], ["prog.o"], env, :cache)
         subject.run("prog.a", ["prog.o"], :cache, env, "ARCMD" => ["special", "AR!", "${_SOURCES}"])
       end
     end
diff --git a/spec/rscons/builders/object_spec.rb b/spec/rscons/builders/object_spec.rb
index 789d8e3..e5eaded 100644
--- a/spec/rscons/builders/object_spec.rb
+++ b/spec/rscons/builders/object_spec.rb
@@ -11,7 +11,7 @@ module Rscons
         cache.stub(:register_build) { }
         FileUtils.stub(:rm_f) { }
         File.stub(:exists?) { false }
-        env.should_receive(:execute).with("CC mod.o", ["llc", "mod.c"]).and_return(true)
+        expect(env).to receive(:execute).with("CC mod.o", ["llc", "mod.c"]).and_return(true)
         subject.run("mod.o", ["mod.c"], cache, env, "CCCMD" => ["llc", "${_SOURCES}"])
       end
 
diff --git a/spec/rscons/builders/preprocess_spec.rb b/spec/rscons/builders/preprocess_spec.rb
index 2a47213..bc07115 100644
--- a/spec/rscons/builders/preprocess_spec.rb
+++ b/spec/rscons/builders/preprocess_spec.rb
@@ -5,12 +5,12 @@ module Rscons
       subject {Preprocess.new}
 
       it "supports overriding CC construction variable" do
-        subject.should_receive(:standard_build).with("Preprocess module.pp", "module.pp", ["my_cpp", "-E", "-o", "module.pp", "module.c"], ["module.c"], env, :cache)
+        expect(subject).to receive(:standard_build).with("Preprocess module.pp", "module.pp", ["my_cpp", "-E", "-o", "module.pp", "module.c"], ["module.c"], env, :cache)
         subject.run("module.pp", ["module.c"], :cache, env, "CC" => "my_cpp")
       end
 
       it "supports overriding CPP_CMD construction variable" do
-        subject.should_receive(:standard_build).with("Preprocess module.pp", "module.pp", ["my_cpp", "module.c"], ["module.c"], env, :cache)
+        expect(subject).to receive(:standard_build).with("Preprocess module.pp", "module.pp", ["my_cpp", "module.c"], ["module.c"], env, :cache)
         subject.run("module.pp", ["module.c"], :cache, env, "CPP_CMD" => ["my_cpp", "${_SOURCES}"])
       end
     end
diff --git a/spec/rscons/builders/program_spec.rb b/spec/rscons/builders/program_spec.rb
index 5fd6caa..ec35081 100644
--- a/spec/rscons/builders/program_spec.rb
+++ b/spec/rscons/builders/program_spec.rb
@@ -5,12 +5,12 @@ module Rscons
       subject {Program.new}
 
       it "supports overriding CC construction variable" do
-        subject.should_receive(:standard_build).with("LD prog", "prog", ["sp-c++", "-o", "prog", "prog.o"], ["prog.o"], env, :cache)
+        expect(subject).to receive(:standard_build).with("LD prog", "prog", ["sp-c++", "-o", "prog", "prog.o"], ["prog.o"], env, :cache)
         subject.run("prog", ["prog.o"], :cache, env, "CC" => "sp-c++")
       end
 
       it "supports overriding LDCMD construction variable" do
-        subject.should_receive(:standard_build).with("LD prog.exe", "prog.exe", ["special", "LD!", "prog.o"], ["prog.o"], env, :cache)
+        expect(subject).to receive(:standard_build).with("LD prog.exe", "prog.exe", ["special", "LD!", "prog.o"], ["prog.o"], env, :cache)
         subject.run("prog.exe", ["prog.o"], :cache, env, "LDCMD" => ["special", "LD!", "${_SOURCES}"])
       end
     end
diff --git a/spec/rscons/cache_spec.rb b/spec/rscons/cache_spec.rb
index 96a85a9..a021491 100644
--- a/spec/rscons/cache_spec.rb
+++ b/spec/rscons/cache_spec.rb
@@ -20,7 +20,7 @@ module Rscons
           $stderr.should_receive(:puts).with(/Warning:.*was.corrupt/)
           c = Cache.instance
           c.send(:initialize!)
-          expect(c.instance_variable_get(:@cache).is_a?(Hash)).to be_true
+          expect(c.instance_variable_get(:@cache).is_a?(Hash)).to be_truthy
         end
       end
     end
@@ -52,12 +52,12 @@ module Rscons
 
       it "returns false when target file does not exist" do
         File.should_receive(:exists?).with("target").and_return(false)
-        expect(build_from({}).up_to_date?("target", "command", [], empty_env)).to be_false
+        expect(build_from({}).up_to_date?("target", "command", [], empty_env)).to be_falsey
       end
 
       it "returns false when target is not registered in the cache" do
         File.should_receive(:exists?).with("target").and_return(true)
-        expect(build_from({}).up_to_date?("target", "command", [], empty_env)).to be_false
+        expect(build_from({}).up_to_date?("target", "command", [], empty_env)).to be_falsey
       end
 
       it "returns false when the target's checksum does not match" do
@@ -65,7 +65,7 @@ module Rscons
         cache = build_from(_cache)
         File.should_receive(:exists?).with("target").and_return(true)
         cache.should_receive(:calculate_checksum).with("target").and_return("def")
-        expect(cache.up_to_date?("target", "command", [], empty_env)).to be_false
+        expect(cache.up_to_date?("target", "command", [], empty_env)).to be_falsey
       end
 
       it "returns false when the build command has changed" do
@@ -73,7 +73,7 @@ module Rscons
         cache = build_from(_cache)
         File.should_receive(:exists?).with("target").and_return(true)
         cache.should_receive(:calculate_checksum).with("target").and_return("abc")
-        expect(cache.up_to_date?("target", "command", [], empty_env)).to be_false
+        expect(cache.up_to_date?("target", "command", [], empty_env)).to be_falsey
       end
 
       it "returns false when there is a new dependency" do
@@ -83,7 +83,7 @@ module Rscons
         cache = build_from(_cache)
         File.should_receive(:exists?).with("target").and_return(true)
         cache.should_receive(:calculate_checksum).with("target").and_return("abc")
-        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_falsey
       end
 
       it "returns false when a dependency's checksum has changed" do
@@ -101,7 +101,7 @@ module Rscons
         cache.should_receive(:calculate_checksum).with("target").and_return("abc")
         cache.should_receive(:calculate_checksum).with("dep.1").and_return("dep.1.chk")
         cache.should_receive(:calculate_checksum).with("dep.2").and_return("dep.2.changed")
-        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_falsey
       end
 
       it "returns false with strict_deps=true when cache has an extra dependency" do
@@ -117,7 +117,7 @@ module Rscons
         cache = build_from(_cache)
         File.should_receive(:exists?).with("target").and_return(true)
         cache.should_receive(:calculate_checksum).with("target").and_return("abc")
-        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env, strict_deps: true)).to be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env, strict_deps: true)).to be_falsey
       end
 
       it "returns false when there is a new user dependency" do
@@ -130,7 +130,7 @@ module Rscons
         env.should_receive(:get_user_deps).with("target").and_return(["file.ld"])
         File.should_receive(:exists?).with("target").and_return(true)
         cache.should_receive(:calculate_checksum).with("target").and_return("abc")
-        expect(cache.up_to_date?("target", "command", ["dep.1"], env)).to be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1"], env)).to be_falsey
       end
 
       it "returns false when a user dependency checksum has changed" do
@@ -153,7 +153,7 @@ module Rscons
         cache.should_receive(:calculate_checksum).with("dep.2").and_return("dep.2.chk")
         cache.should_receive(:calculate_checksum).with("extra.dep").and_return("extra.dep.chk")
         cache.should_receive(:calculate_checksum).with("user.dep").and_return("INCORRECT")
-        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], env)).to be_false
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], env)).to be_falsey
       end
 
       it "returns true when no condition for false is met" do
@@ -172,7 +172,7 @@ module Rscons
         cache.should_receive(:calculate_checksum).with("dep.1").and_return("dep.1.chk")
         cache.should_receive(:calculate_checksum).with("dep.2").and_return("dep.2.chk")
         cache.should_receive(:calculate_checksum).with("extra.dep").and_return("extra.dep.chk")
-        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_true
+        expect(cache.up_to_date?("target", "command", ["dep.1", "dep.2"], empty_env)).to be_truthy
       end
     end
 
diff --git a/spec/rscons/environment_spec.rb b/spec/rscons/environment_spec.rb
index 8802078..d23bc93 100644
--- a/spec/rscons/environment_spec.rb
+++ b/spec/rscons/environment_spec.rb
@@ -4,7 +4,7 @@ module Rscons
       it "adds the default builders when they are not excluded" do
         env = Environment.new
         env.builders.size.should be > 0
-        expect(env.builders.map {|name, builder| builder.is_a?(Builder)}.all?).to be_true
+        expect(env.builders.map {|name, builder| builder.is_a?(Builder)}.all?).to be_truthy
         env.builders.find {|name, builder| name == "Object"}.should_not be_nil
         env.builders.find {|name, builder| name == "Program"}.should_not be_nil
         env.builders.find {|name, builder| name == "Library"}.should_not be_nil
@@ -298,7 +298,7 @@ module Rscons
         env.Object("target.o", ["src1.c", "src2.c"], var: "val")
         target = env.instance_variable_get(:@targets)["target.o"]
         target.should_not be_nil
-        expect(target[:builder].is_a?(Builder)).to be_true
+        expect(target[:builder].is_a?(Builder)).to be_truthy
         expect(target[:sources]).to eq ["src1.c", "src2.c"]
         expect(target[:vars]).to eq({var: "val"})
         expect(target[:args]).to eq []
diff --git a/spec/rscons/varset_spec.rb b/spec/rscons/varset_spec.rb
index 8c12961..f6651b0 100644
--- a/spec/rscons/varset_spec.rb
+++ b/spec/rscons/varset_spec.rb
@@ -45,20 +45,20 @@ module Rscons
       it "returns whether the variable is in the VarSet" do
         v = VarSet.new("CFLAGS" => [], :foo => :bar)
 
-        expect(v.include?("CFLAGS")).to be_true
-        expect(v.include?(:CFLAGS)).to be_false
-        expect(v.include?(:foo)).to be_true
-        expect(v.include?("foo")).to be_false
-        expect(v.include?("bar")).to be_false
+        expect(v.include?("CFLAGS")).to be_truthy
+        expect(v.include?(:CFLAGS)).to be_falsey
+        expect(v.include?(:foo)).to be_truthy
+        expect(v.include?("foo")).to be_falsey
+        expect(v.include?("bar")).to be_falsey
 
         v2 = v.clone
         v2.append("bar" => [])
 
-        expect(v2.include?("CFLAGS")).to be_true
-        expect(v2.include?(:CFLAGS)).to be_false
-        expect(v2.include?(:foo)).to be_true
-        expect(v2.include?("foo")).to be_false
-        expect(v2.include?("bar")).to be_true
+        expect(v2.include?("CFLAGS")).to be_truthy
+        expect(v2.include?(:CFLAGS)).to be_falsey
+        expect(v2.include?(:foo)).to be_truthy
+        expect(v2.include?("foo")).to be_falsey
+        expect(v2.include?("bar")).to be_truthy
       end
     end