4 files changed, 76 insertions, 0 deletions
diff --git a/spec/ruby/core/gc/auto_compact_spec.rb b/spec/ruby/core/gc/auto_compact_spec.rb
new file mode 100644
index 0000000000..33ad1cb56c
--- /dev/null
+++ b/spec/ruby/core/gc/auto_compact_spec.rb
@@ -0,0 +1,24 @@
+require_relative '../../spec_helper'
+
+describe "GC.auto_compact" do
+  it "can set and get a boolean value" do
+    begin
+      GC.auto_compact = GC.auto_compact
+    rescue NotImplementedError # platform does not support autocompact
+      skip
+    end
+
+    original = GC.auto_compact
+    begin
+      GC.auto_compact = !original
+    rescue NotImplementedError # platform does not support autocompact
+      skip
+    end
+
+    begin
+      GC.auto_compact.should == !original
+    ensure
+      GC.auto_compact = original
+    end
+  end
+end
diff --git a/spec/ruby/core/gc/measure_total_time_spec.rb b/spec/ruby/core/gc/measure_total_time_spec.rb
new file mode 100644
index 0000000000..05d4598ebc
--- /dev/null
+++ b/spec/ruby/core/gc/measure_total_time_spec.rb
@@ -0,0 +1,19 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "3.1" do
+  describe "GC.measure_total_time" do
+    before :each do
+      @default = GC.measure_total_time
+    end
+
+    after :each do
+      GC.measure_total_time = @default
+    end
+
+    it "can set and get a boolean value" do
+      original = GC.measure_total_time
+      GC.measure_total_time = !original
+      GC.measure_total_time.should == !original
+    end
+  end
+end
diff --git a/spec/ruby/core/gc/stat_spec.rb b/spec/ruby/core/gc/stat_spec.rb
index eb71fd9691..3b43b28a92 100644
--- a/spec/ruby/core/gc/stat_spec.rb
+++ b/spec/ruby/core/gc/stat_spec.rb
@@ -7,6 +7,16 @@ describe "GC.stat" do
     stat.keys.should.include?(:count)
   end
 
+  it "updates the given hash values" do
+    hash = { count: "hello", __other__: "world" }
+    stat = GC.stat(hash)
+
+    stat.should be_kind_of(Hash)
+    stat.should equal hash
+    stat[:count].should be_kind_of(Integer)
+    stat[:__other__].should == "world"
+  end
+
   it "the values are all Integer since rb_gc_stat() returns size_t" do
     GC.stat.values.each { |value| value.should be_kind_of(Integer) }
   end
@@ -41,4 +51,12 @@ describe "GC.stat" do
     GC.stat(:total_allocated_objects).should be_kind_of(Integer)
     GC.stat[:total_allocated_objects].should be_kind_of(Integer)
   end
+
+  it "raises an error if argument is not nil, a symbol, or a hash" do
+    -> { GC.stat(7) }.should raise_error(TypeError, "non-hash or symbol given")
+  end
+
+  it "raises an error if an unknown key is given" do
+    -> { GC.stat(:foo) }.should raise_error(ArgumentError, "unknown key: foo")
+  end
 end
diff --git a/spec/ruby/core/gc/total_time_spec.rb b/spec/ruby/core/gc/total_time_spec.rb
new file mode 100644
index 0000000000..fcc8f45a83
--- /dev/null
+++ b/spec/ruby/core/gc/total_time_spec.rb
@@ -0,0 +1,15 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "3.1" do
+  describe "GC.total_time" do
+    it "returns an Integer" do
+      GC.total_time.should be_kind_of(Integer)
+    end
+
+    it "increases as collections are run" do
+      time_before = GC.total_time
+      GC.start
+      GC.total_time.should >= time_before
+    end
+  end
+end