Add uncovered test and replace uncovered tests by asserts

test/libsolidity/smtCheckerTests/operators/bitwise_not_fixed_bytes.sol

@@ -1,7 +1,12 @@
 pragma experimental SMTChecker;
+
 contract C {
-  function f() public pure returns (byte) {
-    return (~byte(0xFF));
-  }
+	function f() public pure {
+		// ffff0000 in bytes4
+		bytes4 x = ~bytes4(hex"ffff");
+		assert(x == 0xffff0000); // should fail
+		assert(x == 0x0000ffff); // should hold
+	}
 }
 // ----
+// Warning 6328: (175-198): CHC: Assertion violation happens here.

test/libsolidity/smtCheckerTests/operators/exp.sol

@@ -0,0 +1,10 @@
+pragma experimental SMTChecker;
+contract D {
+	function f(uint x) public pure {
+		assert(x**2 == 4);
+	}
+}
+// ----
+// Warning 5188: (88-92): Assertion checker does not yet implement this operator.
+// Warning 6328: (81-98): CHC: Assertion violation happens here.
+// Warning 5188: (88-92): Assertion checker does not yet implement this operator.

test/libsolidity/smtCheckerTests/special/ether_units.sol

@@ -0,0 +1,15 @@
+pragma experimental SMTChecker;
+contract D {
+	function f() public pure {
+		assert(1000000000000000000 wei == 1 ether);
+		assert(100000000000000000 wei == 1 ether);
+		assert(1000000000 wei == 1 gwei);
+		assert(100000000 wei == 1 gwei);
+		assert(1000000000 gwei == 1 ether);
+		assert(100000000 gwei == 1 ether);
+	}
+}
+// ----
+// Warning 6328: (121-162): CHC: Assertion violation happens here.
+// Warning 6328: (202-233): CHC: Assertion violation happens here.
+// Warning 6328: (275-308): CHC: Assertion violation happens here.

test/libsolidity/smtCheckerTests/special/time_units.sol

@@ -0,0 +1,21 @@
+pragma experimental SMTChecker;
+contract D {
+	function f() public pure {
+		assert(1 == 1 seconds);
+		assert(2 == 1 seconds);
+		assert(2 minutes == 120 seconds);
+		assert(3 minutes == 120 seconds);
+		assert(2 hours == 120 minutes);
+		assert(3 hours == 120 minutes);
+		assert(2 days == 48 hours);
+		assert(4 days == 48 hours);
+		assert(2 weeks == 14 days);
+		assert(25 weeks == 14 days);
+	}
+}
+// ----
+// Warning 6328: (101-123): CHC: Assertion violation happens here.
+// Warning 6328: (163-195): CHC: Assertion violation happens here.
+// Warning 6328: (233-263): CHC: Assertion violation happens here.
+// Warning 6328: (297-323): CHC: Assertion violation happens here.
+// Warning 6328: (357-384): CHC: Assertion violation happens here.